assinging nil to an offset will remove the offset from the AST

3 files changed, 39 insertions, 1 deletions

diff --git a/History.txt b/History.txt
index a931afd0ef..fac98381a6 100644
--- a/History.txt
+++ b/History.txt
@@ -7,11 +7,14 @@
   * SQL Literals may be used as Attribute names
   * Added Arel::Nodes::NamedFunction for representing generic SQL functions
   * Add Arel::SelectManager#limit=
+  * Add Arel::SelectManager#offset
+  * Add Arel::SelectManager#offset=
 
 * Bug fixes
 
   * MSSQL adds TOP to sub selects
   * Assigning nil to take() removes LIMIT from statement.
+  * Assigning nil to offset() removes OFFSET from statement.
 
 * Deprecations
 
diff --git a/lib/arel/select_manager.rb b/lib/arel/select_manager.rb
index 37405b4596..7f533fa91b 100644
--- a/lib/arel/select_manager.rb
+++ b/lib/arel/select_manager.rb
@@ -18,10 +18,19 @@ module Arel
       @ctx.wheres
     end
 
+    def offset
+      @ast.offset && @ast.offset.expr
+    end
+
     def skip amount
-      @ast.offset = Nodes::Offset.new(amount)
+      if amount
+        @ast.offset = Nodes::Offset.new(amount)
+      else
+        @ast.offset = nil
+      end
       self
     end
+    alias :offset= :skip
 
     ###
     # Produces an Arel::Nodes::Exists node
diff --git a/test/test_select_manager.rb b/test/test_select_manager.rb
index efea44d56f..2fe43aa982 100644
--- a/test/test_select_manager.rb
+++ b/test/test_select_manager.rb
@@ -180,6 +180,32 @@ module Arel
       end
     end
 
+    describe 'offset' do
+      it 'should add an offset' do
+        table   = Table.new :users
+        mgr = table.from table
+        mgr.offset = 10
+        mgr.to_sql.must_be_like %{ SELECT FROM "users" OFFSET 10 }
+      end
+
+      it 'should remove an offset' do
+        table   = Table.new :users
+        mgr = table.from table
+        mgr.offset = 10
+        mgr.to_sql.must_be_like %{ SELECT FROM "users" OFFSET 10 }
+
+        mgr.offset = nil
+        mgr.to_sql.must_be_like %{ SELECT FROM "users" }
+      end
+
+      it 'should return the offset' do
+        table   = Table.new :users
+        mgr = table.from table
+        mgr.offset = 10
+        assert_equal 10, mgr.offset
+      end
+    end
+
     describe 'exists' do
       it 'should create an exists clause' do
         table = Table.new(:users)