Can't execute query

SELECT * FROM prodotti WHERE disegnatore =  AND visibile = 0 ORDER BY id ASC LIMIT 56 , 8

MySQL Error: 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 'AND visibile = 0 ORDER BY id ASC LIMIT 56 , 8' at line 1

This script cannot continue, terminating.