MySql报错：Every derived table must have its own alias

Every derived table must have its own alias翻译：每个派生表都需要有自己的别名

即子查询出来得出的表需要给他一个别名！

select count(1)
from (
    SELECT MAX(id)  FROM message
    WHERE STATUS != 2 AND from_id != 1 
) 

例如这个sql语句目标是查询通过子查询得出来的数据有多少行

运行后会出现Every derived table must have its own alias错误！

通过修改：在子查询后面为查询出来的数据添加表名m，就可以查询出来数据

select count(1)
from (
      SELECT MAX(id)  FROM message
      WHERE STATUS != 2 AND from_id != 1
) as m