Increment counter in MySQL

Another specialist thing, but here we go:

mysql> select @m:=0;
+-------+
| @m:=0 |
+-------+
|     0 | 
+-------+
1 row in set (0.00 sec)

mysql> update image_descriptions set ordering=(@m:=@m+1)
    -> where category='gallery';
Query OK, 35 rows affected (0.00 sec)
Rows matched: 35  Changed: 35  Warnings: 0

ie. set a variable to 0 then increment inside the SQL..

Posted 27 Aug 2007, tagged with mysql