—— 阿尔伯特·爱因斯坦

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常用SQL笔记MySQL
2025-04-08 23:46阅读:42评论:0

MySQL之存储过程、游标、遍历结合使用

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drop procedure if exists init_group_val;
delimiter $
create PROCEDURE init_group_val()
BEGIN
DECLARE group_id VARCHAR(64);
 
--
DECLARE done INT DEFAULT FALSE;
-- id
DECLARE cur_account CURSOR FOR SELECT id as group_id FROM tbl_brand_attr_group;
--
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
--
OPEN cur_account;
--
read_loop: LOOP
-- id
FETCH NEXT from cur_account INTO group_id;
IF done THEN
LEAVE read_loop;
END IF;
-- id
call set_attr_val_group_id(group_id);
END LOOP;
CLOSE cur_account;
END $
 
drop procedure if exists set_attr_val_group_id;
delimiter $
create PROCEDURE set_attr_val_group_id(group_id VARCHAR(64))
BEGIN
DECLARE g_id VARCHAR(64);
DECLARE val_id VARCHAR(64);
 
--
DECLARE done INT DEFAULT FALSE;
-- idval
-- basedb,help_topic,,basedb,basedb
DECLARE cur_account CURSOR FOR select a.id as g_id,substring_index(substring_index(a.val,',',b.help_topic_id+1),',',-1) as val_id
from
tbl_brand_attr_group a
join
basedb.help_topic b
on b.help_topic_id < (length(a.val) - length(replace(a.val,',',''))+1)
and a.id=group_id
order by val_id;
--
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
--
OPEN cur_account;
--
read_loop: LOOP
--
FETCH NEXT from cur_account INTO g_id, val_id;
IF done THEN
LEAVE read_loop;
END IF;
-- id
update tbl_brand_attr_val set group_id = g_id WHERE id=val_id;
END LOOP;
CLOSE cur_account;
END $
 
 
ALTER TABLE product.tbl_product_attr_val DROP key_id;
 
--
call init_group_val()
 
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