mySQL 单表删除低于平均分以下的所有数据

Question

delete from t_table where num < ( select avg(num) from
t_table)
执行报错。哪里错了吗？还是有其他方法？

Answer 1

不能先select出同一表中的某些值，再update/delete这个表(在同一语句中)
楼上说的是一种解决方法，也可以这样写，两种都可以
delete from t_table where num < (select avg(num) as num from (select * from t_table)c);
delete from t_table where num < (select * from (select avg(num) as num from t_table)v);
注：as num和最后的c或v别忘记