[MDEV-5702] Incorrect results are returned with NULLIF() Created: 2014-02-19  Updated: 2014-08-16  Resolved: 2014-08-16

Status: Closed
Project: MariaDB Server
Component/s: None
Affects Version/s: 5.5.35, 10.0.8
Fix Version/s: 5.5.38, 10.0.11

Type: Bug Priority: Minor
Reporter: Saulius Gurklys Assignee: Alexander Barkov
Resolution: Fixed Votes: 0
Labels: upstream
Environment:

10.0.8-MariaDB-1~precise mariadb.org binary distribution (64Bit Ubuntu 12.04)

5.5.35-MariaDB-log MariaDB Server (64Bit Centos 6.5)

Attachments: File mariadb-NULLIF-issue.sql    

 Description   

Hi

the attached SQL script shows the problem.

Results in "bad" column, of the last SQL statement, differ from "good" column results, while "bad_len" and "good_len" are the same.

Cast is used for "good" results. No cast for "bad".

 Comments   
Comment by Elena Stepanova [ 2014-02-20 ]

s4uliu5,
Thanks for the report.

This is an upstream (MySQL) bug, reproducible on MySQL 5.5+. In such cases, we also report the bug in bugs.mysql.com, to inform upstream about the issue. Are you willing to do it, or should we do it on your behalf?

bar,

Even though it's an upstream bug, could you please take a quick look, if it's related to the temporal types area that you've been working on, maybe it will be easier to fix it than to wait for the upstream fix.

Here is even smaller test case (although the original one is also quite compact):

SET NAMES utf8;
 
 
 
DROP TABLE IF EXISTS t1;
 
CREATE TABLE t1 (d DATE) ENGINE=MyISAM;
 
 
 
INSERT INTO t1 VALUES ('1999-11-11'),('2014-02-04');
 
 
 
SELECT DISTINCT
 
  d, 
  cast(d as char), 
  nullif(d,"2000-01-01") bad, 
  nullif(cast(d as char),"2000-01-01") good
 
FROM t1;
 
 
 
DROP TABLE t1;

Result:

+------------+-----------------+------+------------+
 
| d          | cast(d as char) | bad  | good       |
 
+------------+-----------------+------+------------+
 
| 1999-11-11 | 1999-11-11      | 199  | 1999-11-11 |
 
| 2014-02-04 | 2014-02-04      | 201  | 2014-02-04 |
 
+------------+-----------------+------+------------+

Comment by Saulius Gurklys [ 2014-02-20 ]

Elena Stepanova,

Just submitted bug report - http://bugs.mysql.com/71777

Thanks.

Comment by Alexander Barkov [ 2014-04-28 ]

Pushed into 5.5.

Comment by Saulius Gurklys [ 2014-08-15 ]

Hello,

just tested on 10.0.13, the issue is gone.

Not tested on latest 5.5 as I do not have one.

Regards,
Saulius

Comment by Saulius Gurklys [ 2014-08-16 ]

Just got a chance to test on 5.5.39, the issue is gone too.

I think this issue could be closed.

Regards,
Saulius

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