maria-discuss team mailing list archive

[Justin Swanhart <greenlion@xxxxxxxxx>]

Hi,

How interesting.

This behavior yields some strange results:
Database changed

mysql>  CREATE TABLE t (c TIMESTAMP) ENGINE=InnoDB;
Query OK, 0 rows affected (0.06 sec)

mysql> insert into t values (1);
Query OK, 1 row affected, 1 warning (0.03 sec)

mysql> show warnings;
+---------+------+----------------------------------------+
| Level   | Code | Message                                |
+---------+------+----------------------------------------+
| Warning | 1265 | Data truncated for column 'c' at row 1 |
+---------+------+----------------------------------------+
1 row in set (0.00 sec)

mysql> select * from t;
+---------------------+
| c                   |
+---------------------+
| 0000-00-00 00:00:00 |
+---------------------+
1 row in set (0.00 sec)

mysql> select * from t where c = 1;
Empty set, 1 warning (0.00 sec)

mysql> show warnings;
+---------+------+-------------------------------------------------------+
| Level   | Code | Message                                               |
+---------+------+-------------------------------------------------------+
| Warning | 1292 | Incorrect datetime value: '1' for column 'c' at row 1 |
+---------+------+-------------------------------------------------------+
1 row in set (0.00 sec)




On Wed, Dec 11, 2013 at 2:08 PM, Sergei Golubchik <serg@xxxxxxxxxxx> wrote:

> Hi, Justin!
>
> On Dec 11, Justin Swanhart wrote:
> > I disagree about as vehemently as possible.  You should get a warning on
> > comparisons between incompatible types that cause float conversions.  You
> > get unexpected wrong results otherwise.  The MySQL warning is therefor
> > critical.
>
> That would be true if you get unexpected wrong results otherwise.
> But here you don't (and no float conversion either, as far as I know).
>
> In this query no explicit type conversion is requested and internal type
> conversons for comparison purposes should not generate warnings as long
> as they stay completely internal. Wrong results means that the internal
> implementation is leaking into the user space - and that's when you
> start needing a warning.
>
> Regards,
> Sergei
>