UPDATE with no subquery throws error: Subquery returns more than 1 row

Question

Can somebody explain to me this... :) (using MySQL 5.6.13)

UPDATE offer SET cosid=1 WHERE id=40;
Query OK, 1 row affected (0.07 sec)
Rows matched: 1  Changed: 1          


        

Answer 1

As ypercube has stated in the comments, and you have confirmed, triggers are the culprit here!