Test case for BUG#15102 : select distinct returns empty result, select count distinct > 0 (correct)

  Reproduced in 5.0.16-nt. Tested to work in 5.0.20
  

mysql-test/r/group_min_max.result

@@ -2070,3 +2070,40 @@ SELECT a FROM t1 WHERE a LIKE 'B%' GROUP BY a;
 a
 BB
 DROP TABLE t1;
+CREATE TABLE t1 (
+a int(11) NOT NULL DEFAULT '0',
+b varchar(16) COLLATE latin1_general_ci NOT NULL DEFAULT '',
+PRIMARY KEY  (a,b)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;
+CREATE PROCEDURE a(x INT)
+BEGIN
+DECLARE rnd INT;
+DECLARE cnt INT;
+WHILE x > 0 DO
+SET rnd= x % 100;
+SET cnt = (SELECT COUNT(*) FROM t1 WHERE a = rnd);
+INSERT INTO t1(a,b) VALUES (rnd, CAST(cnt AS CHAR));
+SET x= x - 1;
+END WHILE;
+END|
+CALL a(1000);
+SELECT a FROM t1 WHERE a=0;
+a
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+SELECT DISTINCT a FROM t1 WHERE a=0;
+a
+0
+SELECT COUNT(DISTINCT a) FROM t1 WHERE a=0;
+COUNT(DISTINCT a)
+1
+DROP TABLE t1;
+DROP PROCEDURE a;

mysql-test/t/group_min_max.test

@@ -736,3 +736,41 @@ SELECT DISTINCT a FROM t1 WHERE a LIKE 'B%';
 SELECT a FROM t1 WHERE a LIKE 'B%' GROUP BY a;
 
 DROP TABLE t1;
+
+
+#
+# Bug #15102: select distinct returns empty result, select count 
+#             distinct > 0 (correct)
+#
+
+CREATE TABLE t1 (
+   a int(11) NOT NULL DEFAULT '0',
+   b varchar(16) COLLATE latin1_general_ci NOT NULL DEFAULT '',
+   PRIMARY KEY  (a,b)
+ ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;
+
+delimiter |;
+
+CREATE PROCEDURE a(x INT)
+BEGIN
+  DECLARE rnd INT;
+  DECLARE cnt INT;
+
+  WHILE x > 0 DO
+    SET rnd= x % 100;
+    SET cnt = (SELECT COUNT(*) FROM t1 WHERE a = rnd);
+    INSERT INTO t1(a,b) VALUES (rnd, CAST(cnt AS CHAR));
+    SET x= x - 1;
+  END WHILE;
+END|
+
+DELIMITER ;|
+
+CALL a(1000);
+
+SELECT a FROM t1 WHERE a=0;
+SELECT DISTINCT a FROM t1 WHERE a=0;
+SELECT COUNT(DISTINCT a) FROM t1 WHERE a=0;
+
+DROP TABLE t1;
+DROP PROCEDURE a;