Mysql delete in 不走索引的

语句格式：

 explain delete  from enrollee where enrollee_id in (select uid from dup_super_id where delete_ind=1);
子查询没多少条，外部的表是大表。初步看执行计划是全表扫描。

analyze table 或者子查询都加了索引，内外表的关联字段属性也都一致，就是不走索引。

想到了写法。用inner join试试：

explain delete a from enrollee a inner join dup_super_id b where a.enrollee_id=b.uid and b.delete_ind=1;

 

为什么delete不行？

1.想到了以前的一个报错：

“SQL删除语句添加表别名：DELETE FROM table_name t WHERE t.id=1;报错了。

Error : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 't where t.id=1' at line 1

原因，删除语句时要么不使