fixing mysql visitor

1 files changed, 42 insertions, 19 deletions

diff --git a/lib/arel/visitors/mysql.rb b/lib/arel/visitors/mysql.rb
index 3b911e826f..cf590598e1 100644
--- a/lib/arel/visitors/mysql.rb
+++ b/lib/arel/visitors/mysql.rb
@@ -2,25 +2,31 @@ module Arel
   module Visitors
     class MySQL < Arel::Visitors::ToSql
       private
-      def visit_Arel_Nodes_Union o, suppress_parens = false
-        left_result = case o.left
+      def visit_Arel_Nodes_Union o, collector, suppress_parens = false
+        unless suppress_parens
+          collector << "( "
+        end
+
+        collector =   case o.left
                       when Arel::Nodes::Union
-                        visit_Arel_Nodes_Union o.left, true
+                        visit_Arel_Nodes_Union o.left, collector, true
                       else
-                        visit o.left
+                        visit o.left, collector
                       end
 
-        right_result = case o.right
+        collector << " UNION "
+
+        collector =    case o.right
                        when Arel::Nodes::Union
-                         visit_Arel_Nodes_Union o.right, true
+                         visit_Arel_Nodes_Union o.right, collector, true
                        else
-                         visit o.right
+                         visit o.right, collector
                        end
 
         if suppress_parens
-          "#{left_result} UNION #{right_result}"
+          collector
         else
-          "( #{left_result} UNION #{right_result} )"
+          collector << " )"
         end
       end
 
@@ -31,26 +37,43 @@ module Arel
       ###
       # :'(
       # http://dev.mysql.com/doc/refman/5.0/en/select.html#id3482214
-      def visit_Arel_Nodes_SelectStatement o
+      def visit_Arel_Nodes_SelectStatement o, collector
         if o.offset && !o.limit
           o.limit = Arel::Nodes::Limit.new(Nodes.build_quoted(18446744073709551615))
         end
         super
       end
 
-      def visit_Arel_Nodes_SelectCore o
+      def visit_Arel_Nodes_SelectCore o, collector
         o.froms ||= Arel.sql('DUAL')
         super
       end
 
-      def visit_Arel_Nodes_UpdateStatement o
-        [
-          "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?),
-          ("ORDER BY #{o.orders.map { |x| visit x }.join(', ')}" unless o.orders.empty?),
-          (visit(o.limit) if o.limit),
-        ].compact.join ' '
+      def visit_Arel_Nodes_UpdateStatement o, collector
+        collector << "UPDATE "
+        collector = visit o.relation, collector
+
+        unless o.values.empty?
+          collector << "SET "
+          collector = inject_join o.values, collector, ', '
+        end
+
+        unless o.wheres.empty?
+          collector << "SET "
+          collector = inject_join o.wheres, collector, ' AND '
+        end
+
+        unless o.orders.empty?
+          collector << "ORDER BY "
+          collector = inject_join o.wheres, collector, ', '
+        end
+
+        if o.limit
+          collector << " "
+          visit(o.limit, collector)
+        else
+          collector
+        end
       end
 
     end