Commit 4233d901 authored by unknown's avatar unknown
Browse files

Fix for bug#5400 "GROUP_CONCAT returns everything twice": 

Don't evaluate the value of GROUP_CONCAT several times for the same 'group', reuse the value instead.


mysql-test/r/group_by.result:
   Testcase for bug#5400
mysql-test/t/group_by.test:
   Testcase for bug#5400
parent 3f70b62c

mysql-test/r/group_by.result

+9 −0
Original line number Diff line number Diff line
@@ -629,3 +629,12 @@ explain SELECT i, COUNT(DISTINCT(i)) FROM t1 GROUP BY j ORDER BY NULL; 
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	6	Using filesort

DROP TABLE t1;

create table t1 ( col1 int, col2 int );

insert into t1 values (1,1),(1,2),(1,3),(2,1),(2,2);

select group_concat( distinct col1 ) as alias from t1

group by col2 having alias like '%';

alias

1,2

1,2

1

drop table t1;

mysql-test/t/group_by.test

+9 −0
Original line number Diff line number Diff line
@@ -456,3 +456,12 @@ INSERT INTO t1 VALUES (1,2),(2,3),(4,5),(3,5),(1,5),(23,5); 
SELECT i, COUNT(DISTINCT(i)) FROM t1 GROUP BY j ORDER BY NULL;

explain SELECT i, COUNT(DISTINCT(i)) FROM t1 GROUP BY j ORDER BY NULL;

DROP TABLE t1;



# Test for BUG#5400: GROUP_CONCAT returns everything twice.

create table t1 ( col1 int, col2 int );

insert into t1 values (1,1),(1,2),(1,3),(2,1),(2,2);

select group_concat( distinct col1 ) as alias from t1

  group by col2 having alias like '%';



drop table t1;

sql/item_sum.cc

+2 −0
Original line number Diff line number Diff line
@@ -2121,6 +2121,8 @@ String* Item_func_group_concat::val_str(String* str) 
  DBUG_ASSERT(fixed == 1);

  if (null_value)

    return 0;

  if (result.length())

    return &result;

  if (tree_mode)

  {

    tree_walk(tree, (tree_walk_action)&dump_leaf_key, (void*)this,