MySQL实用教程(新体系.综合应用实例视频)(第4版）【例9.19】.docx

USE emarket; DROP PROCEDURE IF EXISTS proc_order_delete; CREATE PROCEDURE proc_order_delete() BEGIN DECLARE num int(3); DECLARE cid char(6) ; DECLARE myfound boolean DEFAULT true; DECLARE cur_comms CURSOR FOR SELECT 商品编号,订货数量 FROM orderitems WHERE 订单编号 = @oid; DECLARE CONTINUE HANDLER FOR NOT FOUND SET myfound = false; OPEN cur_comms; mylabel: LOOP FETCH cur_comms INTO cid,num; IF NOT myfound THEN LEAVE mylabel; ELSE UPDATE commodity SET 库存量 = 库存量 + num WHERE 商品编号 = cid; END IF; END LOOP mylabel; CLOSE cur_comms; END ;