Mysql ERROR 1093 (HY000) 错误解决

.版本

1)操作系统

cat /etc/issue
CentOS release 6.6 (Final)
Kernel \r on an \m

cat /proc/version
Linux version 2.6.32-504.el6.x86_64 ([email protected]) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-11) (GCC) ) #1 SMP Wed Oct 15 04:27:16 UTC 2014

2)mysql数据库版本

MySQL --version
MySQL  Ver 14.14 Distrib 5.6.26, for linux-glibc2.5 (x86_64) using  EditLine wrapper

2.问题描述

2.1 发现问题

   在工作过程中遇到过如下的报错：

DELETE FROM cs_user_cp WHERE id IN (
    ->            SELECT cp.id FROM  cs_user_cp cp ,`cs_category_process` p,cs_user u,`cs_position` post WHERE cp.`category_process_id` = p.id  AND u.id = cp.user_id  AND u.`position_code` = post.id AND  p.company_id <> post.company_id);
ERROR 1093 (HY000): You can't specify target table 'cs_user_cp' for update in FROM clause

3.问题分析

   这是因为Mysql 中Delete和Update 语句，不允许子查询中出现update和delete要操作表

4.解决方案

   我们可以通过如下两种变通的方法来解决该问题

方案1

给子查询外面再加一个查询

DELETE FROM cs_user_cp WHERE id IN(SELECT * FROM (
           SELECT cp.id FROM  cs_user_cp cp ,`cs_category_process` p,cs_user u,`cs_position` post WHERE cp.`category_process_id` = p.id  AND u.id = cp.user_id  AND u.`position_code` = post.id AND  p.company_id <> post.company_id) s )

方案2

delete 语句中使用join

DELETE cs_user_cp from cs_user_cp join  (
           SELECT cp.id FROM  cs_user_cp cp ,`cs_category_process` p,cs_user u,`cs_position` post WHERE cp.`category_process_id` = p.id  AND u.id = cp.user_id  AND u.`position_code` = post.id AND  p.company_id <> post.company_id) s on cs_user_cp.id=s.id;