mysql 中 You can't specify target table for update in FROM clause 错误解决方法

You can’t specify target table tbl for update in FROM clause

在mysql中当在一句sql中先后执行对同一张表的select 和 update 或 delete 操作时，就会报错：
You can't specify target table tbl for update in FROM clause

例如：

update tbl as a set a.col = 
(
select b.col from tbl as b where b.id = 1
);

解决方法： 将select字句中的表再嵌套一层select

update tbl as a set a.col = 
(
select c.col from 
 (
select * from tbl as b where b.id = 1
 ) 
as c
);