|
Description:
In theory, the result of sql2(DISTINCT) ⊆ the result of sql1
(SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT !c2 AS f2 FROM t) AS t1); -- sql1
|
(SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT DISTINCT !c2 AS f2 FROM t) AS t1); -- sql2
|
However, the numeric format `9.9999997e-5` changed to `0.00009999999747378752` after adding DISTINCT, seems like a logical bug:
mysql> select version();
|
+-----------------------------------------+
|
| version() |
|
+-----------------------------------------+
|
| 10.11.1-MariaDB-1:10.11.1+maria~ubu2204 |
|
+-----------------------------------------+
|
1 row in set (0.00 sec)
|
|
mysql> (SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT !c2 AS f2 FROM t) AS t1); -- sql1
|
+--------------+
|
| f1 |
|
+--------------+
|
| 9.9999997e-5 |
|
| what |
|
+--------------+
|
2 rows in set (0.00 sec)
|
|
mysql> (SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT DISTINCT !c2 AS f2 FROM t) AS t1); -- sql2
|
+------------------------+
|
| f1 |
|
+------------------------+
|
| 0.00009999999747378752 |
|
| what |
|
+------------------------+
|
2 rows in set (0.00 sec)
|
How to repeat:
drop table if exists t;
|
CREATE TABLE t (c1 FLOAT UNSIGNED,c2 INT);
|
INSERT INTO t VALUES (0.0001,1);
|
|
(SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT !c2 AS f2 FROM t) AS t1); -- sql1
|
(SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT DISTINCT !c2 AS f2 FROM t) AS t1); -- sql2
|
Hope these can be helpful for your debugging:
We look for the first version of the bug in all docker images (with format x.x.x) of https://hub.docker.com/_/mariadb/tags
We found that the bug first occurred in mariadb:10.5.9, it cannot be reproduced in mariadb:10.5.8:
MariaDB [TEST]> select version();
|
+-------------------------------------+
|
| version() |
|
+-------------------------------------+
|
| 10.5.9-MariaDB-1:10.5.9+maria~focal |
|
+-------------------------------------+
|
1 row in set (0.000 sec)
|
|
MariaDB [TEST]> (SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT !c2 AS f2 FROM t) AS t1); -- sql1
|
+--------------+
|
| f1 |
|
+--------------+
|
| 9.9999997e-5 |
|
| what |
|
+--------------+
|
2 rows in set (0.001 sec)
|
|
MariaDB [TEST]> (SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT DISTINCT !c2 AS f2 FROM t) AS t1); -- sql2
|
+------------------------+
|
| f1 |
|
+------------------------+
|
| 0.00009999999747378752 |
|
| what |
|
+------------------------+
|
2 rows in set (0.001 sec)
|
|
MariaDB [TEST]> select version();
|
+-------------------------------------+
|
| version() |
|
+-------------------------------------+
|
| 10.5.8-MariaDB-1:10.5.8+maria~focal |
|
+-------------------------------------+
|
1 row in set (0.000 sec)
|
|
MariaDB [TEST]> (SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT !c2 AS f2 FROM t) AS t1); -- sql1
|
+--------------+
|
| f1 |
|
+--------------+
|
| 9.9999997e-5 |
|
| what |
|
+--------------+
|
2 rows in set (0.001 sec)
|
|
MariaDB [TEST]> (SELECT c1 AS f1 FROM t) UNION ALL (SELECT REPLACE('what', f2, f2) AS f1 FROM (SELECT DISTINCT !c2 AS f2 FROM t) AS t1); -- sql2
|
+--------------+
|
| f1 |
|
+--------------+
|
| 9.9999997e-5 |
|
| what |
|
+--------------+
|
2 rows in set (0.001 sec)
|
|