MySQL 中 delete 語句的子查詢限制

場景一

delete from student where id = (select max(id) from student);

[Err] 1093 - You can't specify target table 'student' for update in FROM clause

描述: 如果子查詢的 from 子句和更新、刪除對象使用同一張表，會出現上述錯誤。

解決方法: 通過給 from 子句中的結果集起別名。

delete from student where id = (select n.max_id from (select max(id) as max_id from student) as n);

上述情況對於 in 子句也適用

delete from student where id in (select id from student where id > 30);

[Err] 1093 - You can't specify target table 'student' for update in FROM clause

解決方法同上:

delete from student where id in (select n.id from (select id from student where id > 30) as n);

場景二

delete from student m where m.id = 1;

[Err] 1064 - You have an error in your SQL syntax;

描述: delete from table 這樣的句子中 table 不能使用別名。

解決方法：去掉別名:

delete from student where id = 1;