Example Trigger Before Insert

gistfile1.sql

DELIMITER $$

DROP TRIGGER /*!50032 IF EXISTS */ `ujicobadb`.`tr_auto_jual`$$

CREATE
    /*!50017 DEFINER = 'root'@'localhost' */
    TRIGGER `tr_auto_jual` BEFORE INSERT ON `tx_jualan` 
    FOR EACH ROW BEGIN
	UPDATE tm_produk SET nQtyJual = (nQtyJual - new.nQty) WHERE sIdProduk=new.sIdProdukfk ;
    END;
$$

DELIMITER ;