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Hi, I want to set up a trigger so that if on an update the prediction field is = 3 then the trigger changes the value to 4 and saves it in the database. The trigger is below.

For some reason I keep getting an error saying: "#1442 - Can't update table 'tzanalytic_forecast_cached' in stored function/trigger because it is already used by statement which invoked this stored function/trigger."

Is this set up the right way?

delimiter $$ 
CREATE TRIGGER no_BoW BEFORE UPDATE ON t FOR EACH ROW 
BEGIN set @prediction = new.prediction; 
UPDATE t SET t.prediction = (SELECT IF(@prediction = '3', '4', @prediction)) WHERE t.event_id = new.event_id AND t.price_tier = new.price_tier; END;
$$ delimiter ;
A: 

Old question, but in case anyone finds this: MySQL triggers can't manipulate the table they are assigned to. All other major DBMS support this feature so hopefully MySQL will add this support soon.

http://forums.mysql.com/read.php?99,122354,240978#msg-240978

Cory House