Update a Book in the live DB Results

opened scifi DB successfully
publisher:
sql: update titles set title = '', publisher = '', copyright = , printed = , printmonth = '', format = '', series = '', serno=NULL, missing = '' where scifiid = ''
Update failed: 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 ' printed = , printmonth = '', format = '', series = '', serno=NULL, missing = ''' at line 1