MySQL Bugs: #1992: Strange behaviour with DISTINCT, SUBQUERY and LIMIT

Bug #1992	Strange behaviour with DISTINCT, SUBQUERY and LIMIT
Submitted:	1 Dec 2003 13:35	Modified:	4 Mar 2004 6:25
Reporter:	jocelyn fournier (Silver Quality Contributor)	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server	Severity:	S3 (Non-critical)
Version:	MySQL 4.1.1	OS:	Linux (Linux)
Assigned to:	Alexey Botchkov	CPU Architecture:	Any

Description:
Hi,

When using combination of DISTINCT, SUBQUERY and LIMIT, MySQL returns some strange results.

Thanks,
  Jocelyn

How to repeat:
CREATE TABLE test (a int(1));
INSERT INTO test VALUES (1),(1),(1),(1),(1),(2),(3),(4),(5);
SELECT (SELECT a) FROM test LIMIT 100;
+------------+
| (SELECT a) |
+------------+
|          1 |
|          1 |
|          1 |
|          1 |
|          1 |
|          2 |
|          3 |
|          4 |
|          5 |
+------------+

it's ok

SELECT DISTINCT (SELECT a) FROM test;
+------------+
| (SELECT a) |
+------------+
|          1 |
|          2 |
|          3 |
|          4 |
|          5 |
+------------+
5 rows in set (0.00 sec)

it's ok too

SELECT DISTINCT (SELECT a) FROM test LIMIT 100;
+------------+
| (SELECT a) |
+------------+
|          5 |
|          5 |
|          5 |
|          5 |
|          5 |
+------------+
5 rows in set (0.00 sec)

Bug ?

However

SELECT DISTINCT (SELECT a+0) FROM test LIMIT 100;
+--------------+
| (SELECT a+0) |
+--------------+
|            1 |
|            2 |
|            3 |
|            4 |
|            5 |
+--------------+
5 rows in set (0.00 sec)

is ok.

Verified against the latest BitKeeper sources.

Thank you.

Hi, Jocelyn!
proposed fix is here:

bk commit - 4.1 tree (hf:1.1657) (06 Dec 2003)

Thank you for your bug report. This issue has been committed to our
source repository of that product and will be incorporated into the
next release.

If necessary, you can access the source repository and build the latest
available version, including the bugfix, yourself. More information 
about accessing the source trees is available at
    http://www.mysql.com/doc/en/Installing_source_tree.html