| Bug #43774 | CAST(CAST(value) as TIME as DATETIME ) returns the wrong value. | ||
|---|---|---|---|
| Submitted: | 20 Mar 2009 23:26 | Modified: | 10 Sep 2013 13:26 |
| Reporter: | Justin Swanhart | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: DML | Severity: | S1 (Critical) |
| Version: | 5.1.30, 4.1, 5.0, 5.1 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
| Tags: | cast, datetime, time, wrong result | ||
[20 Mar 2009 23:57]
Justin Swanhart
Updating the summary to reflect that double cast is being done.
I can understand why CAST('HH:MM:SS' as datetime) returns a bad date, since MySQL will (in my opinion wrongly) try to extract MM-DD-YY format from the input string.
However, when an explicit CAST to TIME is given, even for column references, MySQL returns the wrong result.
CREATE TABLE t1 (f1 time, f2 time);
insert into t1 values ('09:00:00','12:00:00');
mysql> select f1, f2, cast(f1 as datetime), cast(cast(f1 as TIME) as datetime) from t1;
+----------+----------+----------------------+------------------------------------+
| f1 | f2 | cast(f1 as datetime) | cast(cast(f1 as TIME) as datetime) |
+----------+----------+----------------------+------------------------------------+
| 09:00:00 | 12:00:00 | 0000-00-00 09:00:00 | 2009-00-00 00:00:00 |
+----------+----------+----------------------+------------------------------------+
1 row in set (0.00 sec)
[23 Mar 2009 7:22]
Sveta Smirnova
Thank you for the report. Verified as described.
[6 Sep 2013 18:02]
Valeriy Kravchuk
To whom it may concern,
This is what we have in MySQL 5.6:
C:\Program Files\MySQL\MySQL Server 5.5\bin>mysql -uroot -proot -P3314 test
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.6.13-log MySQL Community Server (GPL)
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select cast(cast('21:00:00' as time) as datetime);
+--------------------------------------------+
| cast(cast('21:00:00' as time) as datetime) |
+--------------------------------------------+
| 2013-09-06 21:00:00 |
+--------------------------------------------+
1 row in set (0.03 sec)
mysql> select cast(cast('19:00:00' as time) as datetime);
+--------------------------------------------+
| cast(cast('19:00:00' as time) as datetime) |
+--------------------------------------------+
| 2013-09-06 19:00:00 |
+--------------------------------------------+
1 row in set (0.00 sec)
Same bug is present in 5.5.33 though.
[7 Sep 2013 8:39]
MySQL Verification Team
mysql> select cast(cast('21:00:00' as time) as datetime)a,version();
+---------------------+----------------+
| a | version() |
+---------------------+----------------+
| 2021-00-00 00:00:00 | 5.6.3-m6-debug |
+---------------------+----------------+
1 row in set (0.00 sec)
.....
mysql> select cast(cast('21:00:00' as time) as datetime)a,version();
+---------------------+----------------+
| a | version() |
+---------------------+----------------+
| 2013-09-07 21:00:00 | 5.6.4-m7-debug |
+---------------------+----------------+
1 row in set (0.00 sec)
....
http://dev.mysql.com/doc/relnotes/mysql/5.6/en/news-5-6-4.html
I do not know the exact revision that fixed it, I guess somebody should run bzrfind.
[7 Sep 2013 12:26]
jiang xiaobing
http://bugs.mysql.com/bug.php?id=69352 I think this bug is the same reason like my report one.
[7 Sep 2013 14:22]
Roy Lyseng
5.6.4 added Fractional Seconds Handling, and I think that worklog also added standard-compliant cast of TIME to DATETIME.
[10 Sep 2013 13:26]
Benny Wang
Fixed revno:3402.30.1
Description: Casting of a TIME value to DATETIME treats the time as a string, resulting in a wrong DATETIME without the TIME portion set. How to repeat: mysql> select cast(cast('21:00:00' as time) as datetime); +--------------------------------------------+ | cast(cast('21:00:00' as time) as datetime) | +--------------------------------------------+ | 2021-00-00 00:00:00 | +--------------------------------------------+ 1 row in set (0.00 sec) Suggested fix: CAST to DATETIME from a TIME should yield: 0000-00-00 HH:MI:SS, where 'HH:MI:SS' in the input TIME value in the CAST.