通过该段代码理解mysql存储过程的游标和控制结构 MySQL DELIMITER $$DROP PROCEDURE IF EXISTS `books`.`largest_order`$$CREATE DEFINER=`root`@`192.168.18.248` PROCEDURE `largest_order`(out largest_id int)BEGIN declare this_id int; declare this_am
通过该段代码理解mysql存储过程的游标和控制结构 MySQL
DELIMITER $$
DROP PROCEDURE IF EXISTS `books`.`largest_order`$$
CREATE DEFINER=`root`@`192.168.18.248` PROCEDURE `largest_order`(out largest_id int)
BEGIN
declare this_id int;
declare this_amount float;
declare l_amount float default 0.0;
declare l_id int;
declare done int default 0;
declare cl cursor for select orderid,amount from orders;
declare continue handler for sqlstate '02000' set done =1;
open cl;
repeat
fetch cl into this_id,this_amount;
if not done then
if this_amount > l_amount then
set l_amount = this_amount;
set l_id = this_id;
end if;
end if;
until done end repeat;
close cl;
set largest_id = l_id;
END$$
DELIMITER ;
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