This is my first trigger I'm trying to write. I have two tables. 'stores' and 'zipcodes'. I want to automatically set the latitude and longitude ofthe store usingit's zipcode lookup in the zipcode table. DELIMITER $$; DROP TRIGGER `store_coord`$$ create trigger `store_coord` BEFORE INSERT on `stores` for each row BEGIN UPDATE stores AS s, zipcodes AS z SET s.latitude = z.latitude, s.longitude = z.longitude WHERE s.zip = z.zip AND s.id = NEW.id; END; $$First things first ... Updating a row that doesn't exist yet (BEFORE INSERT trigger) doesn't make sense :-) Why not simply adjust it like this: new.latitude := <your looked up latitude> new.longitude := <your looked up longitude> Given that it's a "before insert", modifying the NEW.<column> values, these will be stored in the table.So when I do this: insert into `stores` (id, name, zip) values (10,'testcompany', 14526);I get this error Error Code : 1442 Can't update table 'stores' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.I must not be doing something right, I've tried all these combinations and ALL give that same error message: DELIMITER $$; DROP TRIGGER `store_coord`$$ create trigger `store_coord` BEFORE INSERT on `stores` for each row BEGIN UPDATE stores AS s, zipcodes AS z SET NEW.latitude = z.latitude, NEW.longitude = z.longitude WHERE s.zip = z.zip AND s.id = NEW.id; END; $$ DELIMITER $$; DROP TRIGGER `store_coord`$$ create trigger `store_coord` BEFORE INSERT on `stores` for each row BEGIN UPDATE stores AS s, zipcodes AS z SET NEW.latitude := z.latitude, NEW.longitude := z.longitude WHERE s.zip = z.zip AND s.id = NEW.id; END; $$ DELIMITER $$; DROP TRIGGER `store_coord`$$ create trigger `store_coord` AFTER INSERT on `stores` for each row BEGIN UPDATE stores AS s, zipcodes AS z SET s.latitude = z.latitude, s.longitude = z.longitude WHERE s.zip = z.zip AND s.id = NEW.id; END; $$ What am I doing wrong?