Question

我需要清理users表和几个相关的表。所以我创建了一个包含userids的变量，我想使用这些值，而不是对每个delete语句使用子查询。

我的语法错误。我做错了什么？

DELIMITER $$
CREATE PROCEDURE `DBNAME`.`SP_PURGE_DISABLED_USERS` ()
BEGIN
  select userid into @disabled_users from USERS where disabled=1;
  delete from USER_ACTIVITY where userid in SELECT userid FROM @disabled_users;
  delete from USER_PREFS where userid in SELECT userid FROM @disabled_users;
  -- <snip> several other related tables to be cleaned up
  delete from USERS where userid in SELECT userid FROM @disabled_users;
END

Answer 1

首先，在程序结束时，您需要设置分隔符：

 END$$

然后将分隔符重置为;

 DELIMITER ;

在此过程中，您的删除语句没有意义。我将停止使用参数来存储select和内部选择的结果：

delete from USER_ACTIVITY 
       WHERE userid in ( select userid from users where disabled=1 );

如果你只有一小部分要删除的禁用用户，你可以使用group concat并在set中找到：

DELIMITER $$
CREATE PROCEDURE `DBNAME`.`SP_PURGE_DISABLED_USERS` ()
BEGIN
  select GROUP_CONCAT(userid) into @disabled_users from USERS where disabled=1;
  delete from USER_ACTIVITY where  FIND_IN_SET(userid, @disabled_users);
  delete from USER_PREFS where FIND_IN_SET(userid, @disabled_users);
  -- <snip> several other related tables to be cleaned up
  delete from USERS where FIND_IN_SET(userid, @disabled_users);
END$$
DELIMITER ;

我不会对成千上万的用户ID执行此操作...但变量中的字符串长度可能有限制。

Answer 2

我决定带一张临时桌子。它将存储过程执行时间减半。

CREATE PROCEDURE `DBNAME`.`SP_PURGE_DISABLED_USERS` ()
BEGIN
  create temporary table disabled_users 
    as (select userid from USERS where disabled=1);
  delete from USER_ACTIVITY where userid in SELECT userid FROM disabled_users;
  delete from USER_PREFS where userid in SELECT userid FROM disabled_users;
  -- <snip> several other related tables to be cleaned up
  delete from USERS where userid in SELECT userid FROM disabled_users;
  drop table disabled_users;
END

感谢所有帮助解决这个问题的人。

在MySQL存储过程中使用变量

2 个答案: