The following query also produces wrong result:
SELECT b, min(a) FROM t1 WHERE a = 7 OR b = 'z' GROUP BY b; +------+--------+ | b | min(a) | +------+--------+ | f | 7 | +------+--------+
While the correct result is:
+------+--------+ | b | min(a) | +------+--------+ | d | 7 | | f | 7 | +------+--------+
The following query also produces wrong result:
SELECT b, min(a) FROM t1 WHERE a = 7 OR b = 'z' GROUP BY b;
+------+--------+
| b | min(a) |
+------+--------+
| f | 7 |
+------+--------+
While the correct result is:
+------+--------+
| b | min(a) |
+------+--------+
| d | 7 |
| f | 7 |
+------+--------+