Merge from mysql-next-mr.

1 files changed, 16 insertions, 1 deletions

diff --git a/sql/sql_select.h b/sql/sql_select.h
index c725316f4dd..8ea7833d853 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -282,7 +282,14 @@ public:
   TABLE    **all_tables,*sort_by_table;
   uint	   tables,const_tables;
   uint	   send_group_parts;
-  bool	   sort_and_group,first_record,full_join,group, no_field_update;
+  /**
+    Indicates that grouping will be performed on the result set during
+    query execution. This field belongs to query execution.
+
+    @see make_group_fields, alloc_group_fields, JOIN::exec
+  */
+  bool     sort_and_group; 
+  bool     first_record,full_join,group, no_field_update;
   bool	   do_send_rows;
   /**
     TRUE when we want to resume nested loop iterations when
@@ -361,6 +368,8 @@ public:
     simple_xxxxx is set if ORDER/GROUP BY doesn't include any references
     to other tables than the first non-constant table in the JOIN.
     It's also set if ORDER/GROUP BY is empty.
+    Used for deciding for or against using a temporary table to compute 
+    GROUP/ORDER BY.
   */
   bool simple_order, simple_group;
   /**
@@ -430,6 +439,7 @@ public:
     tables= 0;
     const_tables= 0;
     join_list= 0;
+    implicit_grouping= FALSE;
     sort_and_group= 0;
     first_record= 0;
     do_send_rows= 1;
@@ -535,6 +545,11 @@ public:
                                         select_lex == unit->fake_select_lex));
   }
 private:
+  /**
+    TRUE if the query contains an aggregate function but has no GROUP
+    BY clause. 
+  */
+  bool implicit_grouping; 
   bool make_simple_join(JOIN *join, TABLE *tmp_table);
 };