making stuff work on mysql

5 files changed, 53 insertions, 12 deletions

diff --git a/lib/arel/crud.rb b/lib/arel/crud.rb
index e060a82941..640189fbe9 100644
--- a/lib/arel/crud.rb
+++ b/lib/arel/crud.rb
@@ -13,16 +13,9 @@ module Arel
       end
       um.table relation
       um.set values
-
-      if @head.orders.empty? && @head.limit.nil?
-        um.wheres = @ctx.wheres
-      else
-        head             = @head.clone
-        core             = head.cores.first
-        core.projections = [relation.primary_key]
-
-        um.wheres = [Nodes::In.new(relation.primary_key, [head])]
-      end
+      um.take @head.limit
+      um.order(*@head.orders)
+      um.wheres = @ctx.wheres
 
       @engine.connection.update um.to_sql, 'AREL'
     end
diff --git a/lib/arel/nodes/update_statement.rb b/lib/arel/nodes/update_statement.rb
index 7a1ce9a7b1..6f21187eb1 100644
--- a/lib/arel/nodes/update_statement.rb
+++ b/lib/arel/nodes/update_statement.rb
@@ -1,12 +1,14 @@
 module Arel
   module Nodes
     class UpdateStatement
-      attr_accessor :relation, :wheres, :values
+      attr_accessor :relation, :wheres, :values, :orders, :limit
 
       def initialize
         @relation = nil
         @wheres   = []
         @values   = []
+        @orders = []
+        @limit  = nil
       end
 
       def initialize_copy other
diff --git a/lib/arel/update_manager.rb b/lib/arel/update_manager.rb
index 484230c4e1..c6a053aaa8 100644
--- a/lib/arel/update_manager.rb
+++ b/lib/arel/update_manager.rb
@@ -5,6 +5,16 @@ module Arel
       @head = Nodes::UpdateStatement.new
     end
 
+    def take limit
+      @head.limit = limit
+      self
+    end
+
+    def order *expr
+      @head.orders = expr
+      self
+    end
+
     ###
     # UPDATE +table+
     def table table
@@ -34,5 +44,13 @@ module Arel
       end
       self
     end
+
+    def to_sql
+      viz = Visitors::ToSql.new @engine
+      unless @engine.connection_pool.spec.config[:adapter] == 'mysql'
+        viz.extend(Visitors::UpdateSql)
+      end
+      viz.accept @head
+    end
   end
 end
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index d6a9a3697f..710b6143ec 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -25,7 +25,9 @@ module Arel
         [
           "UPDATE #{visit o.relation}",
           ("SET #{o.values.map { |value| visit value }.join ', '}" unless o.values.empty?),
-          ("WHERE #{o.wheres.map { |x| visit x }.join ' AND '}" unless o.wheres.empty?)
+          ("WHERE #{o.wheres.map { |x| visit x }.join ' AND '}" unless o.wheres.empty?),
+          ("ORDER BY #{o.orders.map { |x| visit x }.join(', ')}" unless o.orders.empty?),
+          ("LIMIT #{o.limit}" if o.limit),
         ].compact.join ' '
       end
 
diff --git a/lib/arel/visitors/update_sql.rb b/lib/arel/visitors/update_sql.rb
new file mode 100644
index 0000000000..02196a0fb0
--- /dev/null
+++ b/lib/arel/visitors/update_sql.rb
@@ -0,0 +1,26 @@
+module Arel
+  module Visitors
+    module UpdateSql
+      def visit_Arel_Nodes_UpdateStatement o
+        if o.orders.empty? && o.limit.nil?
+          wheres = o.wheres
+        else
+          stmt             = Nodes::SelectStatement.new
+          core             = stmt.cores.first
+          core.froms       = o.relation
+          core.projections = [o.relation.primary_key]
+          stmt.limit       = o.limit
+          stmt.orders      = o.orders
+
+          wheres = [Nodes::In.new(o.relation.primary_key, [stmt])]
+        end
+
+        [
+          "UPDATE #{visit o.relation}",
+          ("SET #{o.values.map { |value| visit value }.join ', '}" unless o.values.empty?),
+          ("WHERE #{wheres.map { |x| visit x }.join ' AND '}" unless wheres.empty?)
+        ].compact.join ' '
+      end
+    end
+  end
+end