bug#23856

1 files changed, 32 insertions, 0 deletions

diff --git a/mysql-test/t/func_gconcat.test b/mysql-test/t/func_gconcat.test
index 0dd82864520..983797f9c4d 100644
--- a/mysql-test/t/func_gconcat.test
+++ b/mysql-test/t/func_gconcat.test
@@ -507,4 +507,36 @@ SELECT GROUP_CONCAT(DISTINCT UCASE(a)) FROM t1;
 SELECT GROUP_CONCAT(DISTINCT UCASE(b)) FROM t1;
 DROP TABLE t1;
 
+#
+# Bug #23856:GROUP_CONCAT and ORDER BY: junk from previous rows for query on I_S
+#
+SET group_concat_max_len= 65535;
+CREATE TABLE t1( a TEXT, b INTEGER );
+INSERT INTO t1 VALUES ( 'a', 0 ), ( 'b', 1 );
+SELECT GROUP_CONCAT( a ORDER BY b ) FROM t1;
+SELECT GROUP_CONCAT(DISTINCT a ORDER BY b) FROM t1;
+SELECT GROUP_CONCAT(DISTINCT a) FROM t1;
+SET group_concat_max_len= 10;
+SELECT GROUP_CONCAT(a ORDER BY b) FROM t1;
+SELECT GROUP_CONCAT(DISTINCT a ORDER BY b) FROM t1;
+SELECT GROUP_CONCAT(DISTINCT a) FROM t1;
+
+SET group_concat_max_len= 65535;
+CREATE TABLE t2( a TEXT );
+INSERT INTO t2 VALUES( REPEAT( 'a', 5000 ) );
+INSERT INTO t2 VALUES( REPEAT( 'b', 5000 ) );
+INSERT INTO t2 VALUES( REPEAT( 'a', 5000 ) );
+SELECT LENGTH( GROUP_CONCAT( DISTINCT a ) ) FROM t2;
+
+CREATE TABLE t3( a TEXT, b INT  );
+INSERT INTO t3 VALUES( REPEAT( 'a', 65534 ), 1 );
+INSERT INTO t3 VALUES( REPEAT( 'a', 65535 ), 2 );
+INSERT INTO t3 VALUES( REPEAT( 'a', 65536 ), 3 );
+SELECT LENGTH( GROUP_CONCAT( a ) ) FROM t3 WHERE b = 1;
+SELECT LENGTH( GROUP_CONCAT( a ) ) FROM t3 WHERE b = 2;
+SELECT LENGTH( GROUP_CONCAT( a ) ) FROM t3 WHERE b = 3;
+
+SET group_concat_max_len= DEFAULT;
+DROP TABLE t1, t2, t3;
+
 --echo End of 5.0 tests