gistfile1.txt

select a.id, max(delivered_at) as last_delivery from alerts a join attempts at on at.alert_id = a.id group by a.id;

That select returns what I want to update alerts with.  So I tried to write an update with GROUP and JOIN.

mysql> update alerts a join attempts att on att.alert_id = a.id set completed_at = max(delivered_at) group by a.id;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'group by a.id' at line 1

It failed....

Can I do this update in SQL, or do I have to write a script in perl python or ruby?