求教sql中我的语句为什么运行不出来

Question

完全小白，求教大佬关于我写的sql语句问题。我感觉自己逻辑上没有错。为什么运行不出来呢。求指正我哪里错了。

我的sql:select * from orders where purch_amt>(select avg(purch_amt) from orders group by customer_id

 

Answer 1

select o.* from orders as o

join (select customer_id, avg(purch_amt) as avg_amt from orders group by customer_id) as a

on o.customer_id=a.customer_id

where o.purch_amt>a.avg_amt