use update.key instead of update.ast.key. make better use of select manager.

1 files changed, 8 insertions, 12 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 4581c16d25..a33e2d8cb0 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -498,18 +498,14 @@ module ActiveRecord
       # in the form of a subsubquery. Ugh!
       def join_to_update(update, select) #:nodoc:
         if select.limit || select.offset || select.orders.any?
-          subsubselect = select.ast.clone
-          subsubselect.cores.last.projections = [update.ast.key]
-          subsubselect = Arel::Nodes::TableAlias.new(
-            Arel::Nodes::Grouping.new(subsubselect),
-            '__active_record_temp'
-          )
-
-          subselect = Arel::Nodes::SelectCore.new
-          subselect.from = subsubselect
-          subselect.projections << Arel::Table.new('__active_record_temp')[update.ast.key.name]
-
-          update.where update.ast.key.in(subselect)
+          subsubselect = select.clone
+          subsubselect.ast.cores.last.projections = [update.key]
+
+          subselect = Arel::SelectManager.new(select.engine)
+          subselect.project Arel.sql(update.key.name)
+          subselect.from subsubselect.as('__active_record_temp')
+
+          update.where update.key.in(subselect)
         else
           update.table select.ast.cores.last.source
           update.wheres = select.constraints