procedure/function/trigger

-- , ; 
-- delimiter ; ; 
delimiter $$
-- rand_string
drop function rand_string $$
-- rand_string(n): n 
create function rand_string(n INT)
returns varchar(255)
begin
 declare chars_str varchar(100）default 'abcefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
 declare return_str varchar(255) default '';
 declare i int default 0;
 while i < n do
  --concat('a','b')：ab
  --substring(str,pos,len): str pos len 
  --rand(): [0,1] 
  set return_str = concat(return_str,substring(chars_str,floor(1 + rand() * 52),1));
  set i = i + 1;
 end while;
 return return_str;
end $$

delimiter ;

-- $$
delimiter $$
-- rand_num(): 
create function rand_num()
returns int(5)
begin
 declare i int defaule 0;
 set i = floor(10 + rand() * 50);
 return i;
end $$
-- ;
delimiter ;

-- $$
delimiter $$
-- 
create procedure insert_emp(in start int(10), in max_num int(10))
begin
 declare i int default 0;
 set autocommit = 0;
 repeat
  set i = i + 1;
  insert into emp values(start + i, rand_string(6), 'SALESMAN'.0001,curdate(), 2000);
  until i = max_num
 end repeat;
 commit;
end $$
-- ;
delimiter ;
-- 
call inert_emp(100001, 4800000);

delimiter $$
DROP PROCEDURE
IF EXISTS update_purchase_pro_refundable$$

CREATE PROCEDURE update_purchase_pro_refundable (
	IN productId VARCHAR (50),
	IN supplierId VARCHAR (50),
	IN shopId VARCHAR(50),
	IN counts INT(10)
)
BEGIN
	DECLARE purchaseProId VARCHAR(50);
	DECLARE error_status INT DEFAULT 0 ; 
	DECLARE datas CURSOR FOR (
				SELECT
					pp.id
				FROM
					purchase_pro pp
				LEFT JOIN purchase pur ON pp.purchase_id = pur.id
				WHERE
					pur.shop_id = shopId
				AND pp.product_id = productId
				AND pp.supplier_id = supplierId
				ORDER BY
					pur.time DESC
				LIMIT counts
			);
	DECLARE CONTINUE HANDLER FOR NOT FOUND SET error_status=1;
	UPDATE purchase_pro pp LEFT JOIN purchase pur ON pp.purchase_id=pur.id
	SET refundable = '0'
	WHERE
		product_id = productId
	AND supplier_id = supplierId
	AND pur.shop_id=shopId;

	OPEN datas;
		FETCH datas INTO purchaseProId;

		REPEAT
		UPDATE purchase_pro SET refundable='1' WHERE id=purchaseProId;
		FETCH datas INTO purchaseProId;
		UNTIL  error_status
		END REPEAT;

	CLOSE  datas;
END
$$
delimiter ;

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