I created Trigger there is no errors but I can't see the answer I use this code given below but it is not working SELECT @Count_No FROM Books WHERE 'No_of_Publisher_year '; Empty set, 1 warning (0.00 sec) :embarasse Code: DELIMITER $$ CREATE TRIGGER No_of_Publisher_year Before Insert ON Books FOR EACH ROW Begin SET @Count_NO=(SELECT Count(@Count_NO) AS 'No_of_publisher_in_year_2007' FROM Books WHERE Copyright=2007); END $$ DELIMITER ;