We're obviously writing specs for arel. No need for a sub directory.

36 files changed, 3083 insertions, 0 deletions

diff --git a/spec/engines/memory/integration/joins/cross_engine_spec.rb b/spec/engines/memory/integration/joins/cross_engine_spec.rb
new file mode 100644
index 0000000000..606f3154c7
--- /dev/null
+++ b/spec/engines/memory/integration/joins/cross_engine_spec.rb
@@ -0,0 +1,52 @@
+require 'spec_helper'
+
+module Arel
+  describe Join do
+    before do
+      @users = Array.new([
+        [1, 'bryan' ],
+        [2, 'emilio' ],
+        [3, 'nick']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+      @photos = Table.new(:photos)
+      @photos.delete
+      @photos.insert(@photos[:id] => 1, @photos[:user_id] => 1, @photos[:camera_id] => 6)
+      @photos.insert(@photos[:id] => 2, @photos[:user_id] => 2, @photos[:camera_id] => 42)
+      # Oracle adapter returns database integers as Ruby integers and not strings
+      @adapter_returns_integer = false
+      adapter_is :oracle do
+        @adapter_returns_integer = true
+      end
+    end
+
+    describe 'when the in memory relation is on the left' do
+      it 'joins across engines' do
+        @users                                         \
+          .join(@photos)                               \
+            .on(@users[:id].eq(@photos[:user_id]))     \
+          .project(@users[:name], @photos[:camera_id]) \
+        .let do |relation|
+          relation.call.should == [
+            Row.new(relation, ['bryan', @adapter_returns_integer ? 6 : '6']),
+            Row.new(relation, ['emilio', @adapter_returns_integer ? 42 : '42'])
+          ]
+        end
+      end
+    end
+
+    describe 'when the in memory relation is on the right' do
+      it 'joins across engines' do
+        @photos                                        \
+          .join(@users)                                \
+            .on(@users[:id].eq(@photos[:user_id]))     \
+          .project(@users[:name], @photos[:camera_id]) \
+        .let do |relation|
+          relation.call.should == [
+            Row.new(relation, ['bryan', @adapter_returns_integer ? 6 : '6']),
+            Row.new(relation, ['emilio', @adapter_returns_integer ? 42 : '42'])
+          ]
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/memory/unit/relations/array_spec.rb b/spec/engines/memory/unit/relations/array_spec.rb
new file mode 100644
index 0000000000..dcec2afa19
--- /dev/null
+++ b/spec/engines/memory/unit/relations/array_spec.rb
@@ -0,0 +1,32 @@
+require 'spec_helper'
+
+module Arel
+  describe Array do
+    before do
+      @relation = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+    end
+
+    describe '#attributes' do
+      it 'manufactures attributes corresponding to the names given on construction' do
+        @relation.attributes.should == [
+          Attribute.new(@relation, :id),
+          Attribute.new(@relation, :name)
+        ]
+      end
+    end
+
+    describe '#call' do
+      it "manufactures an array of hashes of attributes to values" do
+        @relation.call.should == [
+          Row.new(@relation, [1, 'duck']),
+          Row.new(@relation, [2, 'duck']),
+          Row.new(@relation, [3, 'goose'])
+        ]
+      end
+    end
+  end
+end
diff --git a/spec/engines/memory/unit/relations/insert_spec.rb b/spec/engines/memory/unit/relations/insert_spec.rb
new file mode 100644
index 0000000000..987e708e0b
--- /dev/null
+++ b/spec/engines/memory/unit/relations/insert_spec.rb
@@ -0,0 +1,28 @@
+require 'spec_helper'
+
+module Arel
+  describe Insert do
+    before do
+      @relation = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+    end
+
+    describe '#call' do
+      it "manufactures an array of hashes of attributes to values" do
+        @relation                                                         \
+          .insert(@relation[:id] => 4, @relation[:name] => 'guinea fowl') \
+         do |relation|
+           relation.should == [
+             Row.new(relation, [1, 'duck']),
+             Row.new(relation, [2, 'duck']),
+             Row.new(relation, [3, 'goose']),
+             Row.new(relation, [4, 'guinea fowl'])
+           ]
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/memory/unit/relations/join_spec.rb b/spec/engines/memory/unit/relations/join_spec.rb
new file mode 100644
index 0000000000..ed5fe89ef0
--- /dev/null
+++ b/spec/engines/memory/unit/relations/join_spec.rb
@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+module Arel
+  describe Join do
+    before do
+      @relation1 = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+      @relation2 = @relation1.alias
+    end
+
+    describe InnerJoin do
+      describe '#call' do
+        it 'combines the two tables where the predicate obtains' do
+          @relation1                                    \
+            .join(@relation2)                           \
+              .on(@relation1[:id].eq(@relation2[:id]))  \
+          .let do |relation|
+            relation.call.should == [
+              Row.new(relation, [1, 'duck',  1, 'duck' ]),
+              Row.new(relation, [2, 'duck',  2, 'duck' ]),
+              Row.new(relation, [3, 'goose', 3, 'goose'])
+            ]
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/memory/unit/relations/order_spec.rb b/spec/engines/memory/unit/relations/order_spec.rb
new file mode 100644
index 0000000000..9546449bfb
--- /dev/null
+++ b/spec/engines/memory/unit/relations/order_spec.rb
@@ -0,0 +1,27 @@
+require 'spec_helper'
+
+module Arel
+  describe Order do
+    before do
+      @relation = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+    end
+
+    describe '#call' do
+      it 'sorts the relation with the provided ordering' do
+        @relation                     \
+          .order(@relation[:id].desc) \
+        .let do |relation|
+          relation.call.should == [
+            Row.new(relation, [3, 'goose']),
+            Row.new(relation, [2, 'duck' ]),
+            Row.new(relation, [1, 'duck' ])
+          ]
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/memory/unit/relations/project_spec.rb b/spec/engines/memory/unit/relations/project_spec.rb
new file mode 100644
index 0000000000..92ed9fa74b
--- /dev/null
+++ b/spec/engines/memory/unit/relations/project_spec.rb
@@ -0,0 +1,27 @@
+require 'spec_helper'
+
+module Arel
+  describe Project do
+    before do
+      @relation = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+    end
+
+    describe '#call' do
+      it 'retains only the attributes that are provided' do
+        @relation                   \
+          .project(@relation[:id])  \
+        .let do |relation|
+          relation.call.should == [
+            Row.new(relation, [1]),
+            Row.new(relation, [2]),
+            Row.new(relation, [3])
+          ]
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/memory/unit/relations/skip_spec.rb b/spec/engines/memory/unit/relations/skip_spec.rb
new file mode 100644
index 0000000000..089db24cea
--- /dev/null
+++ b/spec/engines/memory/unit/relations/skip_spec.rb
@@ -0,0 +1,26 @@
+require 'spec_helper'
+
+module Arel
+  describe Skip do
+    before do
+      @relation = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+    end
+
+    describe '#call' do
+      it 'removes the first n rows' do
+        @relation   \
+          .skip(1)  \
+        .let do |relation|
+          relation.call.should == [
+            Row.new(relation, [2, 'duck']),
+            Row.new(relation, [3, 'goose']),
+          ]
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/memory/unit/relations/take_spec.rb b/spec/engines/memory/unit/relations/take_spec.rb
new file mode 100644
index 0000000000..16b99872c5
--- /dev/null
+++ b/spec/engines/memory/unit/relations/take_spec.rb
@@ -0,0 +1,26 @@
+require 'spec_helper'
+
+module Arel
+  describe Take do
+    before do
+      @relation = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+    end
+
+    describe '#call' do
+      it 'removes the rows after the first n' do
+        @relation   \
+          .take(2)  \
+        .let do |relation|
+          relation.call.should == [
+            Row.new(relation, [1, 'duck']),
+            Row.new(relation, [2, 'duck']),
+          ]
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/memory/unit/relations/where_spec.rb b/spec/engines/memory/unit/relations/where_spec.rb
new file mode 100644
index 0000000000..b45c009d83
--- /dev/null
+++ b/spec/engines/memory/unit/relations/where_spec.rb
@@ -0,0 +1,39 @@
+require 'spec_helper'
+
+module Arel
+  describe Where do
+    before do
+      @relation = Array.new([
+        [1, 'duck' ],
+        [2, 'duck' ],
+        [3, 'goose']
+      ], [[:id, Attributes::Integer], [:name, Attributes::String]])
+    end
+
+    describe '#call' do
+      it 'filters the relation with the provided predicate' do
+        @relation                       \
+          .where(@relation[:id].lt(3))  \
+        .let do |relation|
+          relation.call.should == [
+            Row.new(relation, [1, 'duck']),
+            Row.new(relation, [2, 'duck']),
+          ]
+        end
+      end
+
+      describe 'when filtering a where relation' do
+        it 'further filters the already-filtered relation with the provided predicate' do
+          @relation                       \
+            .where(@relation[:id].gt(1))  \
+            .where(@relation[:id].lt(3))  \
+          .let do |relation|
+            relation.call.should == [
+              Row.new(relation, [2, 'duck'])
+            ]
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/integration/joins/with_adjacency_spec.rb b/spec/engines/sql/integration/joins/with_adjacency_spec.rb
new file mode 100644
index 0000000000..1a0e28838d
--- /dev/null
+++ b/spec/engines/sql/integration/joins/with_adjacency_spec.rb
@@ -0,0 +1,258 @@
+require 'spec_helper'
+
+module Arel
+  describe Join do
+    before do
+      @relation1 = Table(:users)
+      @relation2 = @relation1.alias
+      @predicate = @relation1[:id].eq(@relation2[:id])
+    end
+
+    describe 'when joining a relation to itself' do
+      describe '#to_sql' do
+        it 'manufactures sql aliasing the table and attributes properly in the join predicate and the where clause' do
+          sql = @relation1.join(@relation2).on(@predicate).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`, `users_2`.`id`, `users_2`.`name`
+              FROM `users`
+                INNER JOIN `users` `users_2`
+                  ON `users`.`id` = `users_2`.`id`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME", "USERS_2"."ID", "USERS_2"."NAME"
+              FROM "USERS"
+                INNER JOIN "USERS" "USERS_2"
+                  ON "USERS"."ID" = "USERS_2"."ID"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name", "users_2"."id", "users_2"."name"
+              FROM "users"
+                INNER JOIN "users" "users_2"
+                  ON "users"."id" = "users_2"."id"
+            })
+          end
+        end
+
+        describe 'when joining with a where on the same relation' do
+          it 'manufactures sql aliasing the tables properly' do
+            sql = @relation1                                 \
+              .join(@relation2.where(@relation2[:id].eq(1))) \
+                .on(@predicate)                              \
+            .to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `users`.`id`, `users`.`name`, `users_2`.`id`, `users_2`.`name`
+                FROM `users`
+                  INNER JOIN `users` `users_2`
+                    ON `users`.`id` = `users_2`.`id` AND `users_2`.`id` = 1
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "USERS"."ID", "USERS"."NAME", "USERS_2"."ID", "USERS_2"."NAME"
+                FROM "USERS"
+                  INNER JOIN "USERS" "USERS_2"
+                    ON "USERS"."ID" = "USERS_2"."ID" AND "USERS_2"."ID" = 1
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "users"."id", "users"."name", "users_2"."id", "users_2"."name"
+                FROM "users"
+                  INNER JOIN "users" "users_2"
+                    ON "users"."id" = "users_2"."id" AND "users_2"."id" = 1
+              })
+            end
+          end
+
+          describe 'when the where occurs before the alias' do
+            it 'manufactures sql aliasing the predicates properly' do
+              relation2 = @relation1.where(@relation1[:id].eq(1)).alias
+
+              sql = @relation1                            \
+                .join(relation2)                          \
+                  .on(relation2[:id].eq(@relation1[:id])) \
+              .to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{
+                  SELECT `users`.`id`, `users`.`name`, `users_2`.`id`, `users_2`.`name`
+                  FROM `users`
+                  INNER JOIN `users` `users_2`
+                    ON `users_2`.`id` = `users`.`id` AND `users_2`.`id` = 1
+                })
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{
+                  SELECT "USERS"."ID", "USERS"."NAME", "USERS_2"."ID", "USERS_2"."NAME"
+                  FROM "USERS"
+                  INNER JOIN "USERS" "USERS_2"
+                    ON "USERS_2"."ID" = "USERS"."ID" AND "USERS_2"."ID" = 1
+                })
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{
+                  SELECT "users"."id", "users"."name", "users_2"."id", "users_2"."name"
+                  FROM "users"
+                  INNER JOIN "users" "users_2"
+                    ON "users_2"."id" = "users"."id" AND "users_2"."id" = 1
+                })
+              end
+            end
+          end
+        end
+
+        describe 'when joining the relation to itself multiple times' do
+          before do
+            @relation3 = @relation1.alias
+          end
+
+          describe 'when joining left-associatively' do
+            it 'manufactures sql aliasing the tables properly' do
+              sql = @relation1                                \
+                .join(@relation2                              \
+                  .join(@relation3)                           \
+                    .on(@relation2[:id].eq(@relation3[:id]))) \
+                  .on(@relation1[:id].eq(@relation2[:id]))                                 \
+              .to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{
+                  SELECT `users`.`id`, `users`.`name`, `users_2`.`id`, `users_2`.`name`, `users_3`.`id`, `users_3`.`name`
+                  FROM `users`
+                    INNER JOIN `users` `users_2`
+                      ON `users`.`id` = `users_2`.`id`
+                    INNER JOIN `users` `users_3`
+                      ON `users_2`.`id` = `users_3`.`id`
+                })
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{
+                  SELECT "USERS"."ID", "USERS"."NAME", "USERS_2"."ID", "USERS_2"."NAME", "USERS_3"."ID", "USERS_3"."NAME"
+                  FROM "USERS"
+                    INNER JOIN "USERS" "USERS_2"
+                      ON "USERS"."ID" = "USERS_2"."ID"
+                    INNER JOIN "USERS" "USERS_3"
+                      ON "USERS_2"."ID" = "USERS_3"."ID"
+                })
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{
+                  SELECT "users"."id", "users"."name", "users_2"."id", "users_2"."name", "users_3"."id", "users_3"."name"
+                  FROM "users"
+                    INNER JOIN "users" "users_2"
+                      ON "users"."id" = "users_2"."id"
+                    INNER JOIN "users" "users_3"
+                      ON "users_2"."id" = "users_3"."id"
+                })
+              end
+            end
+          end
+
+          describe 'when joining right-associatively' do
+            it 'manufactures sql aliasing the tables properly' do
+              sql = @relation1                                              \
+                .join(@relation2).on(@relation1[:id].eq(@relation2[:id]))   \
+                .join(@relation3).on(@relation2[:id].eq(@relation3[:id]))   \
+              .to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{
+                  SELECT `users`.`id`, `users`.`name`, `users_2`.`id`, `users_2`.`name`, `users_3`.`id`, `users_3`.`name`
+                  FROM `users`
+                    INNER JOIN `users` `users_2`
+                      ON `users`.`id` = `users_2`.`id`
+                    INNER JOIN `users` `users_3`
+                      ON `users_2`.`id` = `users_3`.`id`
+                })
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{
+                  SELECT "USERS"."ID", "USERS"."NAME", "USERS_2"."ID", "USERS_2"."NAME", "USERS_3"."ID", "USERS_3"."NAME"
+                  FROM "USERS"
+                    INNER JOIN "USERS" "USERS_2"
+                      ON "USERS"."ID" = "USERS_2"."ID"
+                    INNER JOIN "USERS" "USERS_3"
+                      ON "USERS_2"."ID" = "USERS_3"."ID"
+                })
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{
+                  SELECT "users"."id", "users"."name", "users_2"."id", "users_2"."name", "users_3"."id", "users_3"."name"
+                  FROM "users"
+                    INNER JOIN "users" "users_2"
+                      ON "users"."id" = "users_2"."id"
+                    INNER JOIN "users" "users_3"
+                      ON "users_2"."id" = "users_3"."id"
+                })
+              end
+            end
+          end
+        end
+      end
+
+      describe '[]' do
+        describe 'when given an attribute belonging to both sub-relations' do
+          it 'disambiguates the relation that serves as the ancestor to the attribute' do
+            @relation1          \
+              .join(@relation2) \
+                .on(@predicate) \
+            .should disambiguate_attributes(@relation1[:id], @relation2[:id])
+          end
+
+          describe 'when both relations are compound and only one is an alias' do
+            it 'disambiguates the relation that serves as the ancestor to the attribute' do
+              compound1 = @relation1.where(@predicate)
+              compound2 = compound1.alias
+              compound1           \
+                .join(compound2)  \
+                  .on(@predicate) \
+              .should disambiguate_attributes(compound1[:id], compound2[:id])
+            end
+          end
+
+          describe 'when the left relation is extremely compound' do
+            it 'disambiguates the relation that serves as the ancestor to the attribute' do
+              @relation1            \
+                .where(@predicate)  \
+                .where(@predicate)  \
+                .join(@relation2)   \
+                  .on(@predicate)   \
+              .should disambiguate_attributes(@relation1[:id], @relation2[:id])
+            end
+          end
+
+          describe 'when the right relation is extremely compound' do
+            it 'disambiguates the relation that serves as the ancestor to the attribute' do
+              @relation1                  \
+                .join(                    \
+                  @relation2              \
+                    .where(@predicate)    \
+                    .where(@predicate)    \
+                    .where(@predicate))   \
+                  .on(@predicate)         \
+              .should disambiguate_attributes(@relation1[:id], @relation2[:id])
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/integration/joins/with_aggregations_spec.rb b/spec/engines/sql/integration/joins/with_aggregations_spec.rb
new file mode 100644
index 0000000000..62e1b8baea
--- /dev/null
+++ b/spec/engines/sql/integration/joins/with_aggregations_spec.rb
@@ -0,0 +1,221 @@
+require 'spec_helper'
+
+module Arel
+  describe Join do
+    before do
+      @relation1 = Table(:users)
+      @relation2 = Table(:photos)
+      @predicate = @relation1[:id].eq(@relation2[:user_id])
+    end
+
+    describe 'when joining aggregated relations' do
+      before do
+        @aggregation = @relation2                                           \
+          .group(@relation2[:user_id])                                      \
+          .project(@relation2[:user_id], @relation2[:id].count.as(:cnt))    \
+      end
+
+      describe '#to_sql' do
+        # CLEANUP
+        it '' do
+          sql = @relation1.join(@relation2.take(3)).on(@predicate).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`, `photos_external`.`id`, `photos_external`.`user_id`, `photos_external`.`camera_id`
+              FROM `users`
+              INNER JOIN (SELECT `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id` FROM `photos` LIMIT 3) `photos_external`
+                ON `users`.`id` = `photos_external`.`user_id`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME", "PHOTOS_EXTERNAL"."ID", "PHOTOS_EXTERNAL"."USER_ID", "PHOTOS_EXTERNAL"."CAMERA_ID"
+              FROM "USERS"
+              INNER JOIN (SELECT "PHOTOS"."ID", "PHOTOS"."USER_ID", "PHOTOS"."CAMERA_ID" FROM "PHOTOS" WHERE ROWNUM <= 3) "PHOTOS_EXTERNAL"
+                ON "USERS"."ID" = "PHOTOS_EXTERNAL"."USER_ID"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name", "photos_external"."id", "photos_external"."user_id", "photos_external"."camera_id"
+              FROM "users"
+              INNER JOIN (SELECT "photos"."id", "photos"."user_id", "photos"."camera_id" FROM "photos" LIMIT 3) "photos_external"
+                ON "users"."id" = "photos_external"."user_id"
+            })
+          end
+        end
+
+        describe 'with the aggregation on the right' do
+          it 'manufactures sql joining the left table to a derived table' do
+            sql = @relation1.join(@aggregation).on(@predicate).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `users`.`id`, `users`.`name`, `photos_external`.`user_id`, `photos_external`.`cnt`
+                FROM `users`
+                  INNER JOIN (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` GROUP BY `photos`.`user_id`) `photos_external`
+                    ON `users`.`id` = `photos_external`.`user_id`
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "USERS"."ID", "USERS"."NAME", "PHOTOS_EXTERNAL"."USER_ID", "PHOTOS_EXTERNAL"."CNT"
+                FROM "USERS"
+                  INNER JOIN (SELECT "PHOTOS"."USER_ID", COUNT("PHOTOS"."ID") AS "CNT" FROM "PHOTOS" GROUP BY "PHOTOS"."USER_ID") "PHOTOS_EXTERNAL"
+                    ON "USERS"."ID" = "PHOTOS_EXTERNAL"."USER_ID"
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "users"."id", "users"."name", "photos_external"."user_id", "photos_external"."cnt"
+                FROM "users"
+                  INNER JOIN (SELECT "photos"."user_id", COUNT("photos"."id") AS "cnt" FROM "photos" GROUP BY "photos"."user_id") "photos_external"
+                    ON "users"."id" = "photos_external"."user_id"
+              })
+            end
+          end
+        end
+
+        describe 'with the aggregation on the left' do
+          it 'manufactures sql joining the right table to a derived table' do
+            sql = @aggregation.join(@relation1).on(@predicate).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `photos_external`.`user_id`, `photos_external`.`cnt`, `users`.`id`, `users`.`name`
+                FROM (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` GROUP BY `photos`.`user_id`) `photos_external`
+                  INNER JOIN `users`
+                    ON `users`.`id` = `photos_external`.`user_id`
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "PHOTOS_EXTERNAL"."USER_ID", "PHOTOS_EXTERNAL"."CNT", "USERS"."ID", "USERS"."NAME"
+                FROM (SELECT "PHOTOS"."USER_ID", COUNT("PHOTOS"."ID") AS "CNT" FROM "PHOTOS" GROUP BY "PHOTOS"."USER_ID") "PHOTOS_EXTERNAL"
+                  INNER JOIN "USERS"
+                    ON "USERS"."ID" = "PHOTOS_EXTERNAL"."USER_ID"
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "photos_external"."user_id", "photos_external"."cnt", "users"."id", "users"."name"
+                FROM (SELECT "photos"."user_id", COUNT("photos"."id") AS "cnt" FROM "photos" GROUP BY "photos"."user_id") "photos_external"
+                  INNER JOIN "users"
+                    ON "users"."id" = "photos_external"."user_id"
+              })
+            end
+          end
+        end
+
+        describe 'with the aggregation on both sides' do
+          it 'it properly aliases the aggregations' do
+            aggregation2 = @aggregation.alias
+            sql = @aggregation.join(aggregation2).on(aggregation2[:user_id].eq(@aggregation[:user_id])).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `photos_external`.`user_id`, `photos_external`.`cnt`, `photos_external_2`.`user_id`, `photos_external_2`.`cnt`
+                FROM (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` GROUP BY  `photos`.`user_id`) `photos_external`
+                  INNER JOIN (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` GROUP BY `photos`.`user_id`) `photos_external_2`
+                    ON `photos_external_2`.`user_id` = `photos_external`.`user_id`
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "PHOTOS_EXTERNAL"."USER_ID", "PHOTOS_EXTERNAL"."CNT", "PHOTOS_EXTERNAL_2"."USER_ID", "PHOTOS_EXTERNAL_2"."CNT"
+                FROM (SELECT "PHOTOS"."USER_ID", COUNT("PHOTOS"."ID") AS "CNT" FROM "PHOTOS" GROUP BY  "PHOTOS"."USER_ID") "PHOTOS_EXTERNAL"
+                  INNER JOIN (SELECT "PHOTOS"."USER_ID", COUNT("PHOTOS"."ID") AS "CNT" FROM "PHOTOS" GROUP BY "PHOTOS"."USER_ID") "PHOTOS_EXTERNAL_2"
+                    ON "PHOTOS_EXTERNAL_2"."USER_ID" = "PHOTOS_EXTERNAL"."USER_ID"
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "photos_external"."user_id", "photos_external"."cnt", "photos_external_2"."user_id", "photos_external_2"."cnt"
+                FROM (SELECT "photos"."user_id", COUNT("photos"."id") AS "cnt" FROM "photos" GROUP BY  "photos"."user_id") "photos_external"
+                  INNER JOIN (SELECT "photos"."user_id", COUNT("photos"."id") AS "cnt" FROM "photos" GROUP BY "photos"."user_id") "photos_external_2"
+                    ON "photos_external_2"."user_id" = "photos_external"."user_id"
+              })
+            end
+          end
+        end
+
+        describe 'when the aggration has a where' do
+          describe 'with the aggregation on the left' do
+            it "manufactures sql keeping wheres on the aggregation within the derived table" do
+              sql = @relation1.join(@aggregation.where(@aggregation[:user_id].eq(1))).on(@predicate).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{
+                  SELECT `users`.`id`, `users`.`name`, `photos_external`.`user_id`, `photos_external`.`cnt`
+                  FROM `users`
+                    INNER JOIN (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` WHERE `photos`.`user_id` = 1 GROUP BY `photos`.`user_id`) `photos_external`
+                      ON `users`.`id` = `photos_external`.`user_id`
+                })
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{
+                  SELECT "USERS"."ID", "USERS"."NAME", "PHOTOS_EXTERNAL"."USER_ID", "PHOTOS_EXTERNAL"."CNT"
+                  FROM "USERS"
+                    INNER JOIN (SELECT "PHOTOS"."USER_ID", COUNT("PHOTOS"."ID") AS "CNT" FROM "PHOTOS" WHERE "PHOTOS"."USER_ID" = 1 GROUP BY "PHOTOS"."USER_ID") "PHOTOS_EXTERNAL"
+                      ON "USERS"."ID" = "PHOTOS_EXTERNAL"."USER_ID"
+                })
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{
+                  SELECT "users"."id", "users"."name", "photos_external"."user_id", "photos_external"."cnt"
+                  FROM "users"
+                    INNER JOIN (SELECT "photos"."user_id", COUNT("photos"."id") AS "cnt" FROM "photos" WHERE "photos"."user_id" = 1 GROUP BY "photos"."user_id") "photos_external"
+                      ON "users"."id" = "photos_external"."user_id"
+                })
+              end
+            end
+          end
+
+          describe 'with the aggregation on the right' do
+            it "manufactures sql keeping wheres on the aggregation within the derived table" do
+              sql = @aggregation.where(@aggregation[:user_id].eq(1)).join(@relation1).on(@predicate).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{
+                  SELECT `photos_external`.`user_id`, `photos_external`.`cnt`, `users`.`id`, `users`.`name`
+                  FROM (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` WHERE `photos`.`user_id` = 1 GROUP BY `photos`.`user_id`) `photos_external`
+                    INNER JOIN `users`
+                      ON `users`.`id` = `photos_external`.`user_id`
+                })
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{
+                  SELECT "PHOTOS_EXTERNAL"."USER_ID", "PHOTOS_EXTERNAL"."CNT", "USERS"."ID", "USERS"."NAME"
+                  FROM (SELECT "PHOTOS"."USER_ID", COUNT("PHOTOS"."ID") AS "CNT" FROM "PHOTOS" WHERE "PHOTOS"."USER_ID" = 1 GROUP BY "PHOTOS"."USER_ID") "PHOTOS_EXTERNAL"
+                    INNER JOIN "USERS"
+                      ON "USERS"."ID" = "PHOTOS_EXTERNAL"."USER_ID"
+                })
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{
+                  SELECT "photos_external"."user_id", "photos_external"."cnt", "users"."id", "users"."name"
+                  FROM (SELECT "photos"."user_id", COUNT("photos"."id") AS "cnt" FROM "photos" WHERE "photos"."user_id" = 1 GROUP BY "photos"."user_id") "photos_external"
+                    INNER JOIN "users"
+                      ON "users"."id" = "photos_external"."user_id"
+                })
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/integration/joins/with_compounds_spec.rb b/spec/engines/sql/integration/joins/with_compounds_spec.rb
new file mode 100644
index 0000000000..65fe49d128
--- /dev/null
+++ b/spec/engines/sql/integration/joins/with_compounds_spec.rb
@@ -0,0 +1,137 @@
+require 'spec_helper'
+
+module Arel
+  describe Join do
+    before do
+      @relation1 = Table(:users)
+      @relation2 = Table(:photos)
+      @predicate = @relation1[:id].eq(@relation2[:user_id])
+    end
+
+    describe '#to_sql' do
+      describe 'when the join contains a where' do
+        describe 'and the where is given a string' do
+          it 'does not escape the string' do
+            sql = @relation1                    \
+              .join(@relation2.where("asdf"))   \
+                .on(@predicate)                 \
+            .to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `users`.`id`, `users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id`
+                FROM `users`
+                INNER JOIN `photos`
+                  ON `users`.`id` = `photos`.`user_id` AND asdf
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "USERS"."ID", "USERS"."NAME", "PHOTOS"."ID", "PHOTOS"."USER_ID", "PHOTOS"."CAMERA_ID"
+                FROM "USERS"
+                INNER JOIN "PHOTOS"
+                  ON "USERS"."ID" = "PHOTOS"."USER_ID" AND asdf
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "users"."id", "users"."name", "photos"."id", "photos"."user_id", "photos"."camera_id"
+                FROM "users"
+                INNER JOIN "photos"
+                  ON "users"."id" = "photos"."user_id" AND asdf
+              })
+            end
+          end
+        end
+      end
+
+      describe 'when a compound contains a join' do
+        describe 'and the compound is a where' do
+          it 'manufactures sql disambiguating the tables' do
+            sql = @relation1                  \
+              .where(@relation1[:id].eq(1))   \
+              .join(@relation2)               \
+                .on(@predicate)               \
+              .where(@relation1[:id].eq(1))   \
+            .to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `users`.`id`, `users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id`
+                FROM `users`
+                INNER JOIN `photos`
+                  ON `users`.`id` = `photos`.`user_id`
+                WHERE `users`.`id` = 1
+                  AND `users`.`id` = 1
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "USERS"."ID", "USERS"."NAME", "PHOTOS"."ID", "PHOTOS"."USER_ID", "PHOTOS"."CAMERA_ID"
+                FROM "USERS"
+                INNER JOIN "PHOTOS"
+                  ON "USERS"."ID" = "PHOTOS"."USER_ID"
+                WHERE "USERS"."ID" = 1
+                  AND "USERS"."ID" = 1
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "users"."id", "users"."name", "photos"."id", "photos"."user_id", "photos"."camera_id"
+                FROM "users"
+                INNER JOIN "photos"
+                  ON "users"."id" = "photos"."user_id"
+                WHERE "users"."id" = 1
+                  AND "users"."id" = 1
+              })
+            end
+          end
+        end
+
+        describe 'and the compound is a group' do
+          it 'manufactures sql disambiguating the tables' do
+            sql = @relation1          \
+              .join(@relation2)       \
+                .on(@predicate)       \
+              .group(@relation1[:id]) \
+            .to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `users`.`id`, `users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id`
+                FROM `users`
+                INNER JOIN `photos`
+                  ON `users`.`id` = `photos`.`user_id`
+                GROUP BY `users`.`id`
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "USERS"."ID", "USERS"."NAME", "PHOTOS"."ID", "PHOTOS"."USER_ID", "PHOTOS"."CAMERA_ID"
+                FROM "USERS"
+                INNER JOIN "PHOTOS"
+                  ON "USERS"."ID" = "PHOTOS"."USER_ID"
+                GROUP BY "USERS"."ID"
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "users"."id", "users"."name", "photos"."id", "photos"."user_id", "photos"."camera_id"
+                FROM "users"
+                INNER JOIN "photos"
+                  ON "users"."id" = "photos"."user_id"
+                GROUP BY "users"."id"
+              })
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/engine_spec.rb b/spec/engines/sql/unit/engine_spec.rb
new file mode 100644
index 0000000000..f782f56938
--- /dev/null
+++ b/spec/engines/sql/unit/engine_spec.rb
@@ -0,0 +1,45 @@
+require 'spec_helper'
+
+module Arel
+  describe Sql::Engine do
+    before do
+      @users = Table.new(:users)
+      @users.delete
+    end
+
+    describe "CRUD" do
+      describe "#create" do
+        it "inserts into the relation" do
+          @users.insert @users[:name] => "Bryan"
+          @users.first[@users[:name]].should == "Bryan"
+        end
+      end
+
+      describe "#read" do
+        it "reads from the relation" do
+          @users.insert @users[:name] => "Bryan"
+
+          @users.each do |row|
+            row[@users[:name]].should == "Bryan"
+          end
+        end
+      end
+
+      describe "#update" do
+        it "updates the relation" do
+          @users.insert @users[:name] => "Nick"
+          @users.update @users[:name] => "Bryan"
+          @users.first[@users[:name]].should == "Bryan"
+        end
+      end
+
+      describe "#delete" do
+        it "deletes from the relation" do
+          @users.insert @users[:name] => "Bryan"
+          @users.delete
+          @users.first.should == nil
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/predicates/binary_spec.rb b/spec/engines/sql/unit/predicates/binary_spec.rb
new file mode 100644
index 0000000000..72c8e44888
--- /dev/null
+++ b/spec/engines/sql/unit/predicates/binary_spec.rb
@@ -0,0 +1,140 @@
+require 'spec_helper'
+
+module Arel
+  module Predicates
+    describe Binary do
+      class ConcreteBinary < Binary
+        def predicate_sql
+          "<=>"
+        end
+      end
+
+      before do
+        @relation = Arel::Table.new(:users)
+        @attribute1 = @relation[:id]
+        @attribute2 = @relation[:name]
+      end
+
+      describe "with compound predicates" do
+        before do
+          @operand1 = ConcreteBinary.new(@attribute1, 1)
+          @operand2 = ConcreteBinary.new(@attribute2, "name")
+        end
+
+        describe Or do
+          describe "#to_sql" do
+            it "manufactures sql with an OR operation" do
+              sql = Or.new(@operand1, @operand2).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{(`users`.`id` <=> 1 OR `users`.`name` <=> 'name')})
+              end
+
+              adapter_is :postgresql do
+                sql.should be_like(%Q{("users"."id" <=> 1 OR "users"."name" <=> E'name')})
+              end
+
+              adapter_is :sqlite3 do
+                sql.should be_like(%Q{("users"."id" <=> 1 OR "users"."name" <=> 'name')})
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{("USERS"."ID" <=> 1 OR "USERS"."NAME" <=> 'name')})
+              end
+            end
+          end
+        end
+
+        describe And do
+          describe "#to_sql" do
+            it "manufactures sql with an AND operation" do
+              sql = And.new(@operand1, @operand2).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{(`users`.`id` <=> 1 AND `users`.`name` <=> 'name')})
+              end
+
+              adapter_is :sqlite3 do
+                sql.should be_like(%Q{("users"."id" <=> 1 AND "users"."name" <=> 'name')})
+              end
+
+              adapter_is :postgresql do
+                sql.should be_like(%Q{("users"."id" <=> 1 AND "users"."name" <=> E'name')})
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{("USERS"."ID" <=> 1 AND "USERS"."NAME" <=> 'name')})
+              end
+            end
+          end
+        end
+      end
+
+      describe '#to_sql' do
+        describe 'when relating two attributes' do
+          it 'manufactures sql with a binary operation' do
+            sql = ConcreteBinary.new(@attribute1, @attribute2).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{`users`.`id` <=> `users`.`name`})
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{"USERS"."ID" <=> "USERS"."NAME"})
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{"users"."id" <=> "users"."name"})
+            end
+          end
+        end
+
+        describe 'when relating an attribute and a value' do
+          before do
+            @value = "1-asdf"
+          end
+
+          describe 'when relating to an integer attribute' do
+            it 'formats values as integers' do
+              sql = ConcreteBinary.new(@attribute1, @value).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{`users`.`id` <=> 1})
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{"USERS"."ID" <=> 1})
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{"users"."id" <=> 1})
+              end
+            end
+          end
+
+          describe 'when relating to a string attribute' do
+            it 'formats values as strings' do
+              sql = ConcreteBinary.new(@attribute2, @value).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{`users`.`name` <=> '1-asdf'})
+              end
+
+              adapter_is :sqlite3 do
+                sql.should be_like(%Q{"users"."name" <=> '1-asdf'})
+              end
+
+              adapter_is :postgresql do
+                sql.should be_like(%Q{"users"."name" <=> E'1-asdf'})
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{"USERS"."NAME" <=> '1-asdf'})
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/predicates/equality_spec.rb b/spec/engines/sql/unit/predicates/equality_spec.rb
new file mode 100644
index 0000000000..bfd61185f2
--- /dev/null
+++ b/spec/engines/sql/unit/predicates/equality_spec.rb
@@ -0,0 +1,75 @@
+require 'spec_helper'
+
+module Arel
+  module Predicates
+    describe Equality do
+      before do
+        @relation1 = Arel::Table.new(:users)
+        @relation2 = Arel::Table.new(:photos)
+        @attribute1 = @relation1[:id]
+        @attribute2 = @relation2[:user_id]
+      end
+
+      describe '#to_sql' do
+        describe 'when relating to a non-nil value' do
+          it "manufactures an equality predicate" do
+            sql = Equality.new(@attribute1, @attribute2).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{`users`.`id` = `photos`.`user_id`})
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{"USERS"."ID" = "PHOTOS"."USER_ID"})
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{"users"."id" = "photos"."user_id"})
+            end
+          end
+        end
+
+        describe 'when relation to a nil value' do
+          before do
+            @nil = nil
+          end
+
+          it "manufactures an is null predicate" do
+            sql = Equality.new(@attribute1, @nil).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{`users`.`id` IS NULL})
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{"USERS"."ID" IS NULL})
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{"users"."id" IS NULL})
+            end
+          end
+        end
+
+        describe "when relating to a nil Value" do
+          it "manufactures an IS NULL predicate" do
+            value = nil.bind(@relation1)
+            sql = Equality.new(@attribute1, value).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{`users`.`id` IS NULL})
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{"USERS"."ID" IS NULL})
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{"users"."id" IS NULL})
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/predicates/in_spec.rb b/spec/engines/sql/unit/predicates/in_spec.rb
new file mode 100644
index 0000000000..5d9b2cdcaa
--- /dev/null
+++ b/spec/engines/sql/unit/predicates/in_spec.rb
@@ -0,0 +1,161 @@
+require 'spec_helper'
+
+module Arel
+  module Predicates
+    describe In do
+      before do
+        @relation = Arel::Table.new(:users)
+        @attribute = @relation[:id]
+      end
+
+      describe '#to_sql' do
+        describe 'when relating to an array' do
+          describe 'when the array\'s elements are the same type as the attribute' do
+            before do
+              @array = [1, 2, 3]
+            end
+
+            it 'manufactures sql with a comma separated list' do
+              sql = In.new(@attribute, @array).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{`users`.`id` IN (1, 2, 3)})
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{"USERS"."ID" IN (1, 2, 3)})
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{"users"."id" IN (1, 2, 3)})
+              end
+            end
+          end
+
+          describe 'when the array\'s elements are not same type as the attribute' do
+            before do
+              @array = ['1-asdf', 2, 3]
+            end
+
+            it 'formats values in the array as the type of the attribute' do
+              sql = In.new(@attribute, @array).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{`users`.`id` IN (1, 2, 3)})
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{"USERS"."ID" IN (1, 2, 3)})
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{"users"."id" IN (1, 2, 3)})
+              end
+            end
+          end
+
+          describe 'when the array is empty' do
+            before do
+              @array = []
+            end
+
+            it 'manufactures sql with a comma separated list' do
+              sql = In.new(@attribute, @array).to_sql
+
+              adapter_is :mysql do
+                sql.should be_like(%Q{`users`.`id` IN (NULL)})
+              end
+
+              adapter_is :oracle do
+                sql.should be_like(%Q{"USERS"."ID" IN (NULL)})
+              end
+
+              adapter_is_not :mysql, :oracle do
+                sql.should be_like(%Q{"users"."id" IN (NULL)})
+              end
+            end
+          end
+
+        end
+
+        describe 'when relating to a range' do
+          before do
+            @range = 1..2
+          end
+
+          it 'manufactures sql with a between' do
+            sql = In.new(@attribute, @range).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{`users`.`id` BETWEEN 1 AND 2})
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{"USERS"."ID" BETWEEN 1 AND 2})
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{"users"."id" BETWEEN 1 AND 2})
+            end
+          end
+        end
+
+        describe 'when relating to a time range' do
+          before do
+            @relation = Arel::Table.new(:developers)
+            @attribute = @relation[:created_at]
+            @range = Time.mktime(2010, 01, 01)..Time.mktime(2010, 02, 01)
+          end
+
+          it 'manufactures sql with a between' do
+            sql = In.new(@attribute, @range).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{`developers`.`created_at` BETWEEN '2010-01-01 00:00:00' AND '2010-02-01 00:00:00'})
+            end
+
+            adapter_is :sqlite3 do
+              if RUBY_VERSION < '1.9'
+                sql.should be_like(%Q{"developers"."created_at" BETWEEN '2010-01-01 00:00:00.000000' AND '2010-02-01 00:00:00.000000'})
+              else
+                sql.should be_like(%Q{"developers"."created_at" BETWEEN '2010-01-01 00:00:00' AND '2010-02-01 00:00:00'})
+              end
+            end
+
+            adapter_is :postgresql do
+              sql.should be_like(%Q{"developers"."created_at" BETWEEN '2010-01-01 00:00:00.000000' AND '2010-02-01 00:00:00.000000'})
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{"DEVELOPERS"."CREATED_AT" BETWEEN TO_TIMESTAMP('2010-01-01 00:00:00:000000','YYYY-MM-DD HH24:MI:SS:FF6') AND TO_TIMESTAMP('2010-02-01 00:00:00:000000','YYYY-MM-DD HH24:MI:SS:FF6')})
+            end
+          end
+        end
+
+        describe 'when relating to a relation' do
+          it 'manufactures sql with a subselect' do
+            sql = In.new(@attribute, @relation).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                `users`.`id` IN (SELECT `users`.`id`, `users`.`name` FROM `users`)
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                "USERS"."ID" IN (SELECT "USERS"."ID", "USERS"."NAME" FROM "USERS")
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                "users"."id" IN (SELECT "users"."id", "users"."name" FROM "users")
+              })
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/predicates/predicates_spec.rb b/spec/engines/sql/unit/predicates/predicates_spec.rb
new file mode 100644
index 0000000000..e6130cf267
--- /dev/null
+++ b/spec/engines/sql/unit/predicates/predicates_spec.rb
@@ -0,0 +1,79 @@
+require 'spec_helper'
+
+module Arel
+  module Predicates
+    describe Predicate do
+      before do
+        @relation = Arel::Table.new(:users)
+        @attribute1 = @relation[:id]
+        @attribute2 = @relation[:name]
+        @operand1 = Arel::Predicates::Equality.new(@attribute1, 1)
+        @operand2 = Arel::Predicates::Equality.new(@attribute2, "name")
+      end
+
+      describe "when being combined with another predicate with AND logic" do
+        describe "#to_sql" do
+          it "manufactures sql with an AND operation" do
+            sql = @operand1.and(@operand2).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                (`users`.`id` = 1 AND `users`.`name` = 'name')
+              })
+            end
+
+            adapter_is :sqlite3 do
+              sql.should be_like(%Q{
+                ("users"."id" = 1 AND "users"."name" = 'name')
+              })
+            end
+
+            adapter_is :postgresql do
+              sql.should be_like(%Q{
+                ("users"."id" = 1 AND "users"."name" = E'name')
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                ("USERS"."ID" = 1 AND "USERS"."NAME" = 'name')
+              })
+            end
+          end
+        end
+      end
+
+      describe "when being combined with another predicate with OR logic" do
+        describe "#to_sql" do
+          it "manufactures sql with an OR operation" do
+            sql = @operand1.or(@operand2).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                (`users`.`id` = 1 OR `users`.`name` = 'name')
+              })
+            end
+
+            adapter_is :sqlite3 do
+              sql.should be_like(%Q{
+                ("users"."id" = 1 OR "users"."name" = 'name')
+              })
+            end
+
+            adapter_is :postgresql do
+              sql.should be_like(%Q{
+                ("users"."id" = 1 OR "users"."name" = E'name')
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                ("USERS"."ID" = 1 OR "USERS"."NAME" = 'name')
+              })
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/primitives/attribute_spec.rb b/spec/engines/sql/unit/primitives/attribute_spec.rb
new file mode 100644
index 0000000000..c467d902ad
--- /dev/null
+++ b/spec/engines/sql/unit/primitives/attribute_spec.rb
@@ -0,0 +1,55 @@
+require 'spec_helper'
+
+module Arel
+  describe Attribute do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+
+    describe '#column' do
+      it "returns the corresponding column in the relation" do
+        @attribute.column.should == @relation.column_for(@attribute)
+      end
+    end
+
+    describe '#to_sql' do
+      describe 'for a simple attribute' do
+        it "manufactures sql with an alias" do
+          sql = @attribute.to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{`users`.`id`})
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{"USERS"."ID"})
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{"users"."id"})
+          end
+        end
+      end
+
+      describe 'for an inexistent attribute' do
+        it "manufactures sql" do
+          sql = @relation[:does_not_exist].to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{`users`.`does_not_exist`})
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{"USERS"."DOEST_NOT_EXIST"})
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{"users"."does_not_exist"})
+          end
+        end
+      end
+
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/primitives/expression_spec.rb b/spec/engines/sql/unit/primitives/expression_spec.rb
new file mode 100644
index 0000000000..3b6a7314a2
--- /dev/null
+++ b/spec/engines/sql/unit/primitives/expression_spec.rb
@@ -0,0 +1,28 @@
+require 'spec_helper'
+
+module Arel
+  describe Expression do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+
+    describe '#to_sql' do
+      it "manufactures sql with the expression and alias" do
+        sql = Count.new(@attribute, :alias).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{COUNT(`users`.`id`) AS `alias`})
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{COUNT("USERS"."ID") AS "ALIAS"})
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{COUNT("users"."id") AS "alias"})
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/primitives/literal_spec.rb b/spec/engines/sql/unit/primitives/literal_spec.rb
new file mode 100644
index 0000000000..3bf60100f1
--- /dev/null
+++ b/spec/engines/sql/unit/primitives/literal_spec.rb
@@ -0,0 +1,43 @@
+require 'spec_helper'
+
+module Arel
+  describe SqlLiteral do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      it "manufactures sql with a literal SQL fragment" do
+        sql = @relation.project(Count.new(SqlLiteral.new("*"))).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{SELECT COUNT(*) AS count_id FROM `users`})
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{SELECT COUNT(*) AS count_id FROM "USERS"})
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{SELECT COUNT(*) AS count_id FROM "users"})
+        end
+      end
+
+      it "manufactures expressions on literal SQL fragment" do
+        sql = @relation.project(SqlLiteral.new("2 * credit_limit").sum).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{SELECT SUM(2 * credit_limit) AS sum_id FROM `users`})
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{SELECT SUM(2 * credit_limit) AS sum_id FROM "USERS"})
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{SELECT SUM(2 * credit_limit) AS sum_id FROM "users"})
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/primitives/value_spec.rb b/spec/engines/sql/unit/primitives/value_spec.rb
new file mode 100644
index 0000000000..807090e31a
--- /dev/null
+++ b/spec/engines/sql/unit/primitives/value_spec.rb
@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+module Arel
+  describe Value do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      it "appropriately quotes the value" do
+        Value.new(1, @relation).to_sql.should be_like('1')
+
+        adapter_is_not :postgresql do
+          Value.new('asdf', @relation).to_sql.should be_like("'asdf'")
+        end
+
+        adapter_is :postgresql do
+          Value.new('asdf', @relation).to_sql.should be_like("E'asdf'")
+        end
+      end
+    end
+
+    describe '#format' do
+      it "returns the sql of the provided object" do
+        Value.new(1, @relation).format(@relation[:id]).should == @relation[:id].to_sql
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/alias_spec.rb b/spec/engines/sql/unit/relations/alias_spec.rb
new file mode 100644
index 0000000000..a6fd7ab036
--- /dev/null
+++ b/spec/engines/sql/unit/relations/alias_spec.rb
@@ -0,0 +1,53 @@
+require 'spec_helper'
+
+module Arel
+  describe Alias do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      describe 'when there is no ambiguity' do
+        it 'does not alias table names anywhere a table name can appear' do
+          sql = @relation                 \
+            .where(@relation[:id].eq(1))  \
+            .order(@relation[:id])        \
+            .project(@relation[:id])      \
+            .group(@relation[:id])        \
+            .alias                        \
+          .to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`
+              FROM `users`
+              WHERE `users`.`id` = 1
+              GROUP BY `users`.`id`
+              ORDER BY `users`.`id` ASC
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID"
+              FROM "USERS"
+              WHERE "USERS"."ID" = 1
+              GROUP BY "USERS"."ID"
+              ORDER BY "USERS"."ID" ASC
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id"
+              FROM "users"
+              WHERE "users"."id" = 1
+              GROUP BY "users"."id"
+              ORDER BY "users"."id" ASC
+            })
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/delete_spec.rb b/spec/engines/sql/unit/relations/delete_spec.rb
new file mode 100644
index 0000000000..302a13c688
--- /dev/null
+++ b/spec/engines/sql/unit/relations/delete_spec.rb
@@ -0,0 +1,83 @@
+require 'spec_helper'
+
+module Arel
+  describe Deletion do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      it 'manufactures sql deleting a table relation' do
+        sql = Deletion.new(@relation).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{DELETE FROM `users`})
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{DELETE FROM "USERS"})
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{DELETE FROM "users"})
+        end
+      end
+
+      it 'manufactures sql deleting a where relation' do
+        sql = Deletion.new(@relation.where(@relation[:id].eq(1))).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            DELETE
+            FROM `users`
+            WHERE `users`.`id` = 1
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            DELETE
+            FROM "USERS"
+            WHERE "USERS"."ID" = 1
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            DELETE
+            FROM "users"
+            WHERE "users"."id" = 1
+          })
+        end
+      end
+
+      it "manufactures sql deleting a ranged relation" do
+        sql = Deletion.new(@relation.take(1)).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            DELETE
+            FROM `users`
+            LIMIT 1
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            DELETE
+            FROM "USERS"
+            WHERE ROWNUM <= 1
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            DELETE
+            FROM "users"
+            LIMIT 1
+          })
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/from_spec.rb b/spec/engines/sql/unit/relations/from_spec.rb
new file mode 100644
index 0000000000..0be3ac0f9a
--- /dev/null
+++ b/spec/engines/sql/unit/relations/from_spec.rb
@@ -0,0 +1,64 @@
+require 'spec_helper'
+
+module Arel
+  describe Table do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      it "manufactures a simple select query" do
+        sql = @relation.from("workers").to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `users`.`id`, `users`.`name`
+            FROM workers
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            SELECT "USERS"."ID", "USERS"."NAME"
+            FROM workers
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM workers
+          })
+        end
+      end
+    end
+
+    describe '#to_sql' do
+      it "overrides and use last from clause given " do
+        sql = @relation.from("workers").from("users").to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `users`.`id`, `users`.`name`
+            FROM users
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            SELECT "USERS"."ID", "USERS"."NAME"
+            FROM users
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM users
+          })
+        end
+      end
+    end
+
+  end
+end
diff --git a/spec/engines/sql/unit/relations/group_spec.rb b/spec/engines/sql/unit/relations/group_spec.rb
new file mode 100644
index 0000000000..72a9f4e99e
--- /dev/null
+++ b/spec/engines/sql/unit/relations/group_spec.rb
@@ -0,0 +1,72 @@
+require 'spec_helper'
+
+module Arel
+  describe Group do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+
+    describe '#to_sql' do
+      describe 'when given a predicate' do
+        it "manufactures sql with where clause conditions" do
+          sql = Group.new(@relation, @attribute).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+              GROUP BY `users`.`id`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+              GROUP BY "USERS"."ID"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+              GROUP BY "users"."id"
+            })
+          end
+        end
+      end
+
+      describe 'when given a string' do
+        it "passes the string through to the where clause" do
+          sql = Group.new(@relation, 'asdf').to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+              GROUP BY asdf
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+              GROUP BY asdf
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+              GROUP BY asdf
+            })
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/having_spec.rb b/spec/engines/sql/unit/relations/having_spec.rb
new file mode 100644
index 0000000000..fe6f3cc520
--- /dev/null
+++ b/spec/engines/sql/unit/relations/having_spec.rb
@@ -0,0 +1,45 @@
+require 'spec_helper'
+
+module Arel
+  describe Having do
+    before do
+      @relation = Table.new(:developers)
+    end
+
+    describe '#to_sql' do
+      describe 'when given a predicate' do
+        it "manufactures sql with where clause conditions" do
+          sql = @relation.group(@relation[:department]).having("MIN(salary) > 1000").to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `developers`.`id`, `developers`.`name`, `developers`.`salary`, `developers`.`department`, `developers`.`created_at`
+              FROM `developers`
+              GROUP BY `developers`.`department`
+              HAVING MIN(salary) > 1000
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "DEVELOPERS"."ID", "DEVELOPERS"."NAME", "DEVELOPERS"."SALARY", "DEVELOPERS"."DEPARTMENT", "DEVELOPERS"."CREATED_AT"
+              FROM "DEVELOPERS"
+              GROUP BY "DEVELOPERS"."DEPARTMENT"
+              HAVING MIN(salary) > 1000
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "developers"."id", "developers"."name", "developers"."salary", "developers"."department", "developers"."created_at"
+              FROM "developers"
+              GROUP BY "developers"."department"
+              HAVING MIN(salary) > 1000
+            })
+          end
+        end
+      end
+    end
+  end
+end
+
diff --git a/spec/engines/sql/unit/relations/insert_spec.rb b/spec/engines/sql/unit/relations/insert_spec.rb
new file mode 100644
index 0000000000..4b412093e4
--- /dev/null
+++ b/spec/engines/sql/unit/relations/insert_spec.rb
@@ -0,0 +1,143 @@
+require 'spec_helper'
+
+module Arel
+  describe Insert do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      it 'manufactures sql inserting data when given multiple rows' do
+        pending 'it should insert multiple rows' do
+          @insertion = Insert.new(@relation, [@relation[:name] => "nick", @relation[:name] => "bryan"])
+
+          @insertion.to_sql.should be_like("
+            INSERT
+            INTO `users`
+            (`name`) VALUES ('nick'), ('bryan')
+          ")
+        end
+      end
+
+      it 'manufactures sql inserting data when given multiple values' do
+        @insertion = Insert.new(@relation, @relation[:id] => "1", @relation[:name] => "nick")
+
+        adapter_is :mysql do
+          @insertion.to_sql.should be_like(%Q{
+            INSERT
+            INTO `users`
+            (`id`, `name`) VALUES (1, 'nick')
+          })
+        end
+
+        adapter_is :sqlite3 do
+          @insertion.to_sql.should be_like(%Q{
+            INSERT
+            INTO "users"
+            ("id", "name") VALUES (1, 'nick')
+          })
+        end
+
+        adapter_is :postgresql do
+          @insertion.to_sql.should be_like(%Q{
+            INSERT
+            INTO "users"
+            ("id", "name") VALUES (1, E'nick')
+            RETURNING "id"
+          })
+        end
+
+        adapter_is :oracle do
+          @insertion.to_sql.should be_like(%Q{
+            INSERT
+            INTO "USERS"
+            ("ID", "NAME") VALUES (1, 'nick')
+          })
+        end
+      end
+
+      describe 'when given values whose types correspond to the types of the attributes' do
+        before do
+          @insertion = Insert.new(@relation, @relation[:name] => "nick")
+        end
+
+        it 'manufactures sql inserting data' do
+          adapter_is :mysql do
+            @insertion.to_sql.should be_like(%Q{
+              INSERT
+              INTO `users`
+              (`name`) VALUES ('nick')
+            })
+          end
+
+          adapter_is :sqlite3 do
+            @insertion.to_sql.should be_like(%Q{
+              INSERT
+              INTO "users"
+              ("name") VALUES ('nick')
+            })
+          end
+
+          adapter_is :postgresql do
+            @insertion.to_sql.should be_like(%Q{
+              INSERT
+              INTO "users"
+              ("name") VALUES (E'nick')
+              RETURNING "id"
+            })
+          end
+
+          adapter_is :oracle do
+            @insertion.to_sql.should be_like(%Q{
+              INSERT
+              INTO "USERS"
+              ("NAME") VALUES ('nick')
+            })
+          end
+        end
+      end
+
+      describe 'when given values whose types differ from from the types of the attributes' do
+        before do
+          @insertion = Insert.new(@relation, @relation[:id] => '1-asdf')
+        end
+
+        it 'manufactures sql inserting data' do
+          adapter_is :mysql do
+            @insertion.to_sql.should be_like(%Q{
+              INSERT
+              INTO `users`
+              (`id`) VALUES (1)
+            })
+          end
+
+          adapter_is :sqlite3 do
+            @insertion.to_sql.should be_like(%Q{
+              INSERT
+              INTO "users"
+              ("id") VALUES (1)
+            })
+          end
+
+          adapter_is :postgresql do
+            @insertion.to_sql.should be_like(%Q{
+              INSERT
+              INTO "users"
+              ("id") VALUES (1)
+              RETURNING "id"
+            })
+          end
+
+          adapter_is :oracle do
+            @insertion.to_sql.should be_like(%Q{
+              INSERT
+              INTO "USERS"
+              ("ID") VALUES (1)
+            })
+          end
+
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/join_spec.rb b/spec/engines/sql/unit/relations/join_spec.rb
new file mode 100644
index 0000000000..cbbcb18244
--- /dev/null
+++ b/spec/engines/sql/unit/relations/join_spec.rb
@@ -0,0 +1,180 @@
+require 'spec_helper'
+
+module Arel
+  describe Join do
+    before do
+      @relation1 = Table.new(:users)
+      @relation2 = Table.new(:photos)
+      @predicate1 = @relation1[:id].eq(@relation2[:user_id])
+
+      @relation3 = Table.new(:users, :as => :super_users)
+      @relation4 = Table.new(:photos, :as => :super_photos)
+
+      @predicate2 = @relation3[:id].eq(@relation2[:user_id])
+      @predicate3 = @relation3[:id].eq(@relation4[:user_id])
+    end
+
+    describe '#to_sql' do
+
+      describe 'when joining with another relation' do
+        it 'manufactures sql joining the two tables on the predicate' do
+          sql = InnerJoin.new(@relation1, @relation2, @predicate1).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id`
+              FROM `users`
+                INNER JOIN `photos` ON `users`.`id` = `photos`.`user_id`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME", "PHOTOS"."ID", "PHOTOS"."USER_ID", "PHOTOS"."CAMERA_ID"
+              FROM "USERS"
+                INNER JOIN "PHOTOS" ON "USERS"."ID" = "PHOTOS"."USER_ID"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name", "photos"."id", "photos"."user_id", "photos"."camera_id"
+              FROM "users"
+                INNER JOIN "photos" ON "users"."id" = "photos"."user_id"
+            })
+          end
+        end
+
+        describe 'when joining with another relation with an aliased table' do
+          it 'manufactures sql joining the two tables on the predicate respecting table aliasing' do
+            sql = InnerJoin.new(@relation3, @relation2, @predicate2).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `super_users`.`id`, `super_users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id`
+                FROM `users` `super_users`
+                  INNER JOIN `photos` ON `super_users`.`id` = `photos`.`user_id`
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "SUPER_USERS"."ID", "SUPER_USERS"."NAME", "PHOTOS"."ID", "PHOTOS"."USER_ID", "PHOTOS"."CAMERA_ID"
+                FROM "USERS" "SUPER_USERS"
+                  INNER JOIN "PHOTOS" ON "SUPER_USERS"."ID" = "PHOTOS"."USER_ID"
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "super_users"."id", "super_users"."name", "photos"."id", "photos"."user_id", "photos"."camera_id"
+                FROM "users" "super_users"
+                  INNER JOIN "photos" ON "super_users"."id" = "photos"."user_id"
+              })
+            end
+          end
+        end
+
+        describe 'when joining with two relations with aliased tables' do
+          it 'manufactures sql joining the two tables on the predicate respecting table aliasing' do
+            sql = InnerJoin.new(@relation3, @relation4, @predicate3).to_sql
+
+            adapter_is :mysql do
+              sql.should be_like(%Q{
+                SELECT `super_users`.`id`, `super_users`.`name`, `super_photos`.`id`, `super_photos`.`user_id`, `super_photos`.`camera_id`
+                FROM `users` `super_users`
+                  INNER JOIN `photos` `super_photos` ON `super_users`.`id` = `super_photos`.`user_id`
+              })
+            end
+
+            adapter_is :oracle do
+              sql.should be_like(%Q{
+                SELECT "SUPER_USERS"."ID", "SUPER_USERS"."NAME", "SUPER_PHOTOS"."ID", "SUPER_PHOTOS"."USER_ID", "SUPER_PHOTOS"."CAMERA_ID"
+                FROM "USERS" "SUPER_USERS"
+                  INNER JOIN "PHOTOS" "SUPER_PHOTOS" ON "SUPER_USERS"."ID" = "SUPER_PHOTOS"."USER_ID"
+              })
+            end
+
+            adapter_is_not :mysql, :oracle do
+              sql.should be_like(%Q{
+                SELECT "super_users"."id", "super_users"."name", "super_photos"."id", "super_photos"."user_id", "super_photos"."camera_id"
+                FROM "users" "super_users"
+                  INNER JOIN "photos" "super_photos" ON "super_users"."id" = "super_photos"."user_id"
+              })
+            end
+          end
+        end
+
+      end
+
+      describe 'when joining with a string' do
+        it "passes the string through to the where clause" do
+          sql = StringJoin.new(@relation1, "INNER JOIN asdf ON fdsa").to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+                INNER JOIN asdf ON fdsa
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+                INNER JOIN asdf ON fdsa
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+                INNER JOIN asdf ON fdsa
+            })
+          end
+        end
+
+        it "passes the string when there are multiple string joins" do
+          relation = StringJoin.new(@relation1, "INNER JOIN asdf ON fdsa")
+          relation = StringJoin.new(relation, "INNER JOIN lifo ON fifo")
+          sql = StringJoin.new(relation, "INNER JOIN hatful ON hallow").to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+                INNER JOIN asdf ON fdsa
+                INNER JOIN lifo ON fifo
+                INNER JOIN hatful ON hallow
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+                INNER JOIN asdf ON fdsa
+                INNER JOIN lifo ON fifo
+                INNER JOIN hatful ON hallow
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+                INNER JOIN asdf ON fdsa
+                INNER JOIN lifo ON fifo
+                INNER JOIN hatful ON hallow
+            })
+          end
+        end
+
+    end
+
+
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/lock_spec.rb b/spec/engines/sql/unit/relations/lock_spec.rb
new file mode 100644
index 0000000000..72a8a2e457
--- /dev/null
+++ b/spec/engines/sql/unit/relations/lock_spec.rb
@@ -0,0 +1,86 @@
+require 'spec_helper'
+
+module Arel
+  describe Lock do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      it "manufactures a simple select query lock" do
+        sql = @relation.lock.to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `users`.`id`, `users`.`name`
+            FROM `users` FOR UPDATE
+          })
+        end
+
+        adapter_is :postgresql do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users" FOR UPDATE
+          })
+        end
+
+        adapter_is :sqlite3 do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users"
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            SELECT "USERS"."ID", "USERS"."NAME"
+            FROM "USERS" FOR UPDATE
+          })
+
+          sql_with_order_by = @relation.order(@relation[:id]).take(1).lock.to_sql
+          sql_with_order_by.should be_like(%Q{
+            SELECT "USERS"."ID", "USERS"."NAME"
+            FROM "USERS"
+            WHERE "ID" IN (select * from
+                          (SELECT "ID" FROM "USERS" ORDER BY "USERS"."ID" ASC)
+                          where rownum <= 1)
+            FOR UPDATE
+          })
+
+        end
+      end
+
+      it "manufactures a select query locking with a given lock" do
+        sql = @relation.lock("LOCK IN SHARE MODE").to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `users`.`id`, `users`.`name`
+            FROM `users` LOCK IN SHARE MODE
+          })
+        end
+
+        adapter_is :postgresql do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users" LOCK IN SHARE MODE
+          })
+        end
+
+        adapter_is :sqlite3 do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users"
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            SELECT "USERS"."ID", "USERS"."NAME"
+            FROM "USERS" LOCK IN SHARE MODE
+          })
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/order_spec.rb b/spec/engines/sql/unit/relations/order_spec.rb
new file mode 100644
index 0000000000..3c9d9ef598
--- /dev/null
+++ b/spec/engines/sql/unit/relations/order_spec.rb
@@ -0,0 +1,161 @@
+require 'spec_helper'
+
+module Arel
+  describe Order do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+
+    describe '#to_sql' do
+      describe "when given an attribute" do
+        it "manufactures sql with an order clause populated by the attribute" do
+          sql = Order.new(@relation, @attribute).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+              ORDER BY `users`.`id` ASC
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+              ORDER BY "USERS"."ID" ASC
+            })
+
+            distinct_attributes = ActiveRecord::Base.connection.distinct('"USERS"."NAME"', '"USERS"."ID"')
+            @relation.project(distinct_attributes).order(@relation[:id]).to_sql.should be_like(%Q{
+              SELECT DISTINCT "USERS"."NAME",
+              FIRST_VALUE("USERS"."ID") OVER (PARTITION BY "USERS"."NAME" ORDER BY "USERS"."ID") AS alias_0__
+              FROM "USERS"
+              ORDER BY alias_0__
+            })
+
+            distinct_attributes = ActiveRecord::Base.connection.distinct('"USERS"."NAME"', '"USERS"."ID" DESC')
+            @relation.project(distinct_attributes).order('"USERS"."ID" DESC').to_sql.should be_like(%Q{
+              SELECT DISTINCT "USERS"."NAME",
+              FIRST_VALUE("USERS"."ID") OVER (PARTITION BY "USERS"."NAME" ORDER BY "USERS"."ID" DESC) AS alias_0__
+              FROM "USERS"
+              ORDER BY alias_0__ DESC
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+              ORDER BY "users"."id" ASC
+            })
+          end
+        end
+      end
+
+      describe "when given multiple attributes" do
+        before do
+          @another_attribute = @relation[:name]
+        end
+
+        it "manufactures sql with an order clause populated by comma-separated attributes" do
+          sql = Order.new(@relation, @attribute, @another_attribute).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+              ORDER BY `users`.`id` ASC, `users`.`name` ASC
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+              ORDER BY "USERS"."ID" ASC, "USERS"."NAME" ASC
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+              ORDER BY "users"."id" ASC, "users"."name" ASC
+            })
+          end
+        end
+      end
+
+      describe "when given a string" do
+        before do
+          @string = "asdf"
+        end
+
+        it "passes the string through to the order clause" do
+          sql = Order.new(@relation, @string).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+              ORDER BY asdf
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+              ORDER BY asdf
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+              ORDER BY asdf
+            })
+          end
+        end
+      end
+
+      describe "when ordering an ordered relation" do
+        before do
+          @ordered_relation = Order.new(@relation, @attribute)
+          @another_attribute = @relation[:name]
+        end
+
+        it "manufactures sql with the order clause of the last ordering preceding the first ordering" do
+          sql = Order.new(@ordered_relation, @another_attribute).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+              ORDER BY `users`.`name` ASC, `users`.`id` ASC
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+              ORDER BY "USERS"."NAME" ASC, "USERS"."ID" ASC
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+              ORDER BY "users"."name" ASC, "users"."id" ASC
+            })
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/project_spec.rb b/spec/engines/sql/unit/relations/project_spec.rb
new file mode 100644
index 0000000000..e73c7775a1
--- /dev/null
+++ b/spec/engines/sql/unit/relations/project_spec.rb
@@ -0,0 +1,143 @@
+require 'spec_helper'
+
+module Arel
+  describe Project do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+
+    describe '#to_sql' do
+      describe 'when given an attribute' do
+        it "manufactures sql with a limited select clause" do
+          sql = Project.new(@relation, @attribute).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`
+              FROM `users`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID"
+              FROM "USERS"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id"
+              FROM "users"
+            })
+          end
+        end
+      end
+
+      describe 'when given a relation' do
+        before do
+          @scalar_relation = Project.new(@relation, @relation[:name])
+        end
+
+        it "manufactures sql with scalar selects" do
+          sql = Project.new(@relation, @scalar_relation).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT (SELECT `users`.`name` FROM `users`) AS `users` FROM `users`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT (SELECT "USERS"."NAME" FROM "USERS") AS "USERS" FROM "USERS"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT (SELECT "users"."name" FROM "users") AS "users" FROM "users"
+            })
+          end
+        end
+      end
+
+      describe 'when given a string' do
+        it "passes the string through to the select clause" do
+          sql = Project.new(@relation, 'asdf').to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT asdf FROM `users`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT asdf FROM "USERS"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT asdf FROM "users"
+            })
+          end
+        end
+      end
+
+      describe 'when given an expression' do
+        it 'manufactures sql with expressions' do
+          sql = @relation.project(@attribute.count).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT COUNT(`users`.`id`) AS count_id
+              FROM `users`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT COUNT("USERS"."ID") AS count_id
+              FROM "USERS"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT COUNT("users"."id") AS count_id
+              FROM "users"
+            })
+          end
+        end
+
+        it 'manufactures sql with distinct expressions' do
+          sql = @relation.project(@attribute.count(true)).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT COUNT(DISTINCT `users`.`id`) AS count_id
+              FROM `users`
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT COUNT(DISTINCT "USERS"."ID") AS count_id
+              FROM "USERS"
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT COUNT(DISTINCT "users"."id") AS count_id
+              FROM "users"
+            })
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/skip_spec.rb b/spec/engines/sql/unit/relations/skip_spec.rb
new file mode 100644
index 0000000000..41b80d12d8
--- /dev/null
+++ b/spec/engines/sql/unit/relations/skip_spec.rb
@@ -0,0 +1,41 @@
+require 'spec_helper'
+
+module Arel
+  describe Skip do
+    before do
+      @relation = Table.new(:users)
+      @skipped = 4
+    end
+
+    describe '#to_sql' do
+      it "manufactures sql with limit and offset" do
+        sql = Skip.new(@relation, @skipped).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `users`.`id`, `users`.`name`
+            FROM `users`
+            OFFSET 4
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            select * from (select raw_sql_.*, rownum raw_rnum_ from
+            (SELECT "USERS"."ID", "USERS"."NAME"
+            FROM "USERS") raw_sql_)
+            where raw_rnum_ > 4
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users"
+            OFFSET 4
+          })
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/table_spec.rb b/spec/engines/sql/unit/relations/table_spec.rb
new file mode 100644
index 0000000000..6afd9964a4
--- /dev/null
+++ b/spec/engines/sql/unit/relations/table_spec.rb
@@ -0,0 +1,129 @@
+require 'spec_helper'
+
+module Arel
+  describe Table do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      it "manufactures a simple select query" do
+        sql = @relation.to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `users`.`id`, `users`.`name`
+            FROM `users`
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            SELECT "USERS"."ID", "USERS"."NAME"
+            FROM "USERS"
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users"
+          })
+        end
+      end
+    end
+
+    describe '#as' do
+      it "manufactures a simple select query using aliases" do
+        sql = @relation.as(:super_users).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `super_users`.`id`, `super_users`.`name`
+            FROM `users` `super_users`
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            SELECT "SUPER_USERS"."ID", "SUPER_USERS"."NAME"
+            FROM "USERS" "SUPER_USERS"
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            SELECT "super_users"."id", "super_users"."name"
+            FROM "users" "super_users"
+          })
+        end
+      end
+
+      it "does not apply alias if it's same as the table name" do
+        sql = @relation.as(:users).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `users`.`id`, `users`.`name`
+            FROM `users`
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            SELECT "USERS"."ID", "USERS"."NAME"
+            FROM "USERS"
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users"
+          })
+        end
+      end
+
+    end
+
+    describe '#column_for' do
+      it "returns the column corresponding to the attribute" do
+        @relation.column_for(@relation[:id]).should == @relation.columns.detect { |c| c.name == 'id' }
+      end
+    end
+
+    describe '#attributes' do
+      it 'manufactures attributes corresponding to columns in the table' do
+        @relation.attributes.should == [
+          Attribute.new(@relation, :id),
+          Attribute.new(@relation, :name)
+        ]
+      end
+
+      describe '#reset' do
+        it "reloads columns from the database" do
+          lambda { @relation.engine.stub!(:columns => []) }.should_not change { @relation.attributes }
+          lambda { @relation.reset                        }.should     change { @relation.attributes }
+        end
+      end
+    end
+
+    describe 'hashing' do
+      it "implements hash equality" do
+        Table.new(:users).should     hash_the_same_as(Table.new(:users))
+        Table.new(:users).should_not hash_the_same_as(Table.new(:photos))
+      end
+    end
+
+    describe '#engine' do
+      it "defaults to global engine" do
+        Table.engine = engine = Sql::Engine.new
+        Table.new(:users).engine.should == engine
+      end
+
+      it "can be specified" do
+        Table.new(:users, engine = Sql::Engine.new).engine.should == engine
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/take_spec.rb b/spec/engines/sql/unit/relations/take_spec.rb
new file mode 100644
index 0000000000..9f2967a0bd
--- /dev/null
+++ b/spec/engines/sql/unit/relations/take_spec.rb
@@ -0,0 +1,49 @@
+require 'spec_helper'
+
+module Arel
+  describe Take do
+    before do
+      @relation = Table.new(:users)
+      @taken = 4
+    end
+
+    describe '#to_sql' do
+      it "manufactures sql with limit and offset" do
+        sql = Take.new(@relation, @taken).to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            SELECT `users`.`id`, `users`.`name`
+            FROM `users`
+            LIMIT 4
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            SELECT "USERS"."ID", "USERS"."NAME"
+            FROM "USERS"
+            WHERE ROWNUM <= 4
+          })
+
+          sql_with_order_by = Take.new(@relation.order(@relation[:id]), @taken).to_sql
+          sql_with_order_by.should be_like(%Q{
+            select * from
+            (SELECT "USERS"."ID", "USERS"."NAME"
+            FROM "USERS"
+            ORDER BY "USERS"."ID" ASC)
+            where rownum <= 4
+          })
+        end
+
+        adapter_is_not :mysql, :oracle do
+          sql.should be_like(%Q{
+            SELECT "users"."id", "users"."name"
+            FROM "users"
+            LIMIT 4
+          })
+        end
+      end
+    end
+  end
+end
diff --git a/spec/engines/sql/unit/relations/update_spec.rb b/spec/engines/sql/unit/relations/update_spec.rb
new file mode 100644
index 0000000000..cc2ad9913b
--- /dev/null
+++ b/spec/engines/sql/unit/relations/update_spec.rb
@@ -0,0 +1,203 @@
+require 'spec_helper'
+
+class User
+  def self.primary_key
+    "id"
+  end
+end
+
+module Arel
+  describe Update do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#to_sql' do
+      it "manufactures sql updating attributes when given multiple attributes" do
+        sql = Update.new(@relation, @relation[:id] => 1, @relation[:name] => "nick").to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            UPDATE `users`
+            SET `id` = 1, `name` = 'nick'
+          })
+        end
+
+        adapter_is :sqlite3 do
+          sql.should be_like(%Q{
+            UPDATE "users"
+            SET "id" = 1, "name" = 'nick'
+          })
+        end
+
+        adapter_is :postgresql do
+          sql.should be_like(%Q{
+            UPDATE "users"
+            SET "id" = 1, "name" = E'nick'
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            UPDATE "USERS"
+            SET "ID" = 1, "NAME" = 'nick'
+          })
+        end
+      end
+
+      it "manufactures sql updating attributes when given a ranged relation" do
+        sql = Update.new(@relation.take(1), @relation[:name] => "nick").to_sql
+
+        adapter_is :mysql do
+          sql.should be_like(%Q{
+            UPDATE `users`
+            SET `name` = 'nick'
+            LIMIT 1
+          })
+        end
+
+        adapter_is :sqlite3 do
+          sql.should be_like(%Q{
+            UPDATE "users" SET
+            "name" = 'nick'
+            WHERE "id" IN (SELECT "id" FROM "users"  LIMIT 1)
+          })
+        end
+
+        adapter_is :postgresql do
+          sql.should be_like(%Q{
+            UPDATE "users" SET
+            "name" = E'nick'
+            WHERE "id" IN (SELECT "id" FROM "users"  LIMIT 1)
+          })
+        end
+
+        adapter_is :oracle do
+          sql.should be_like(%Q{
+            UPDATE "USERS" SET
+            "NAME" = 'nick'
+            WHERE "ID" IN (SELECT "ID" FROM "USERS" WHERE ROWNUM <= 1)
+          })
+
+          sql_with_order_by = Update.new(@relation.order(@relation[:id]).take(1), @relation[:name] => "nick").to_sql
+          sql_with_order_by.should be_like(%Q{
+            UPDATE "USERS" SET
+            "NAME" = 'nick'
+            WHERE "ID" IN (select * from
+                          (SELECT "ID" FROM "USERS" ORDER BY "USERS"."ID" ASC)
+                          where rownum <= 1)
+          })
+        end
+      end
+
+      describe 'when given values whose types correspond to the types of the attributes' do
+        before do
+          @update = Update.new(@relation, @relation[:name] => "nick")
+        end
+
+        it 'manufactures sql updating attributes' do
+          adapter_is :mysql do
+            @update.to_sql.should be_like(%Q{
+              UPDATE `users`
+              SET `name` = 'nick'
+            })
+          end
+
+          adapter_is :sqlite3 do
+            @update.to_sql.should be_like(%Q{
+              UPDATE "users"
+              SET "name" = 'nick'
+            })
+          end
+
+          adapter_is :postgresql do
+            @update.to_sql.should be_like(%Q{
+              UPDATE "users"
+              SET "name" = E'nick'
+            })
+          end
+
+          adapter_is :oracle do
+            @update.to_sql.should be_like(%Q{
+              UPDATE "USERS"
+              SET "NAME" = 'nick'
+            })
+          end
+        end
+      end
+
+      describe 'when given values whose types differ from from the types of the attributes' do
+        before do
+          @update = Update.new(@relation, @relation[:id] => '1-asdf')
+        end
+
+        it 'manufactures sql updating attributes' do
+          adapter_is :mysql do
+            @update.to_sql.should be_like(%Q{
+              UPDATE `users`
+              SET `id` = 1
+            })
+          end
+
+          adapter_is :oracle do
+            @update.to_sql.should be_like(%Q{
+              UPDATE "USERS"
+              SET "ID" = 1
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            @update.to_sql.should be_like(%Q{
+              UPDATE "users"
+              SET "id" = 1
+            })
+          end
+        end
+      end
+
+      describe 'when the relation is a where' do
+        before do
+          @update = Update.new(
+            @relation.where(@relation[:id].eq(1)),
+            @relation[:name] => "nick"
+          )
+        end
+
+        it 'manufactures sql updating a where relation' do
+          adapter_is :mysql do
+            @update.to_sql.should be_like(%Q{
+              UPDATE `users`
+              SET `name` = 'nick'
+              WHERE `users`.`id` = 1
+            })
+          end
+
+          adapter_is :sqlite3 do
+            @update.to_sql.should be_like(%Q{
+              UPDATE "users"
+              SET "name" = 'nick'
+              WHERE "users"."id" = 1
+            })
+          end
+
+          adapter_is :postgresql do
+            @update.to_sql.should be_like(%Q{
+              UPDATE "users"
+              SET "name" = E'nick'
+              WHERE "users"."id" = 1
+            })
+          end
+
+          adapter_is :oracle do
+            @update.to_sql.should be_like(%Q{
+              UPDATE "USERS"
+              SET "NAME" = 'nick'
+              WHERE "USERS"."ID" = 1
+            })
+          end
+        end
+      end
+    end
+
+  end
+end
diff --git a/spec/engines/sql/unit/relations/where_spec.rb b/spec/engines/sql/unit/relations/where_spec.rb
new file mode 100644
index 0000000000..5f559efad3
--- /dev/null
+++ b/spec/engines/sql/unit/relations/where_spec.rb
@@ -0,0 +1,72 @@
+require 'spec_helper'
+
+module Arel
+  describe Where do
+    before do
+      @relation = Table.new(:users)
+      @predicate = @relation[:id].eq(1)
+    end
+
+    describe '#to_sql' do
+      describe 'when given a predicate' do
+        it "manufactures sql with where clause conditions" do
+          sql = Where.new(@relation, @predicate).to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+              WHERE `users`.`id` = 1
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+              WHERE "USERS"."ID" = 1
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+              WHERE "users"."id" = 1
+            })
+          end
+        end
+      end
+
+      describe 'when given a string' do
+        it "passes the string through to the where clause" do
+          sql = Where.new(@relation, 'asdf').to_sql
+
+          adapter_is :mysql do
+            sql.should be_like(%Q{
+              SELECT `users`.`id`, `users`.`name`
+              FROM `users`
+              WHERE asdf
+            })
+          end
+
+          adapter_is :oracle do
+            sql.should be_like(%Q{
+              SELECT "USERS"."ID", "USERS"."NAME"
+              FROM "USERS"
+              WHERE asdf
+            })
+          end
+
+          adapter_is_not :mysql, :oracle do
+            sql.should be_like(%Q{
+              SELECT "users"."id", "users"."name"
+              FROM "users"
+              WHERE asdf
+            })
+          end
+        end
+      end
+    end
+  end
+end