I need to update 2 datetime columns, and I need them to be exactly the same, using mysql version 4.1.20. I'm using this query:
mysql> update table set last_update=now(), last_monitor=now() where id=1;
mysql> update table set last_update=last_monitor=now() where id=1;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1 Changed: 0 Warnings: 0
Found a solution:
mysql> UPDATE table SET last_update=now(), last_monitor=last_update WHERE id=1;
I found this in MySQL Docs and after a few tests it works:
the following statement sets col2 to the current (updated) col1 value, not the original col1 value. The result is that col1 and col2 have the same value. This behavior differs from standard SQL.
UPDATE t1 SET col1 = col1 + 1, col2 = col1;
On the second question, don't have any answers, did find nothing on mysql docs about this.