From 5bc16fd9545a92ba2690ab0687e6bdf76d92757a Mon Sep 17 00:00:00 2001
From: "gkodinov/kgeorge@macbook.gmz" <>
Date: Fri, 8 Sep 2006 19:04:46 +0300
Subject: Bug #21540: Subqueries with no from and aggregate functions return   
          wrong results  Mark the containing Item(s) (Item_subselect
 descendant usually) of  a subselect as containing aggregate functions if it
 has references  to aggregates functions that are calculated outside its
 context.  This tels end_send_group() not to make an Item_subselect descendant
 in  select list a copy and causes the correct value being returned.

---
 sql/item_sum.cc | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

(limited to 'sql/item_sum.cc')

diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 0d2a5b3b080..7dc90b11771 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -246,7 +246,27 @@ bool Item_sum::register_sum_func(THD *thd, Item **ref)
       aggr_sl->inner_sum_func_list->next= this;
     }
     aggr_sl->inner_sum_func_list= this;
-      
+    aggr_sl->with_sum_func= 1;
+
+    /* 
+      Mark Item_subselect(s) as containing aggregate function all the way up
+      to aggregate function's calculation context.
+      Note that we must not mark the Item of calculation context itself
+      because with_sum_func on the calculation context st_select_lex is
+      already set above.
+
+      with_sum_func being set for an Item means that this Item refers 
+      (somewhere in it, e.g. one of its arguments if it's a function) directly
+      or through intermediate items to an aggregate function that is calculated
+      in a context "outside" of the Item (e.g. in the current or outer select).
+
+      with_sum_func being set for an st_select_lex means that this st_select_lex
+      has aggregate functions directly referenced (i.e. not through a sub-select).
+    */
+    for (sl= thd->lex->current_select; 
+         sl && sl != aggr_sl && sl->master_unit()->item;
+         sl= sl->master_unit()->outer_select() )
+      sl->master_unit()->item->with_sum_func= 1;
   }
   return FALSE;
 }
-- 
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