Question

如何更改此查询，在此我想将max转换为子查询，当我输入sql时，唯一会出现的是id和名字。

SELECT staff.staff_id,staff.firstname,max(payment.amount)
from payment ,staff
where payment.staff_id=staff.staff_id

Answer 1

使用显式连接

SELECT staff.staff_id,staff.firstname,max(payment.amount)
from payment join staff
on  payment.staff_id=staff.staff_id

但是我想你想要

   SELECT staff.staff_id,staff.firstname,p.amount
    from payment p join staff
    on  p.staff_id=staff.staff_id
    where p.amount= select max(amount) from payment

Answer 2

您可以尝试使用相关子查询

SELECT staff.staff_id,staff.firstname
from payment inner join staff
on payment.staff_id=staff.staff_id where payment.amount in (select max(payment.amount) from payment)

Answer 3

从JOIN到（相关）子查询：

SELECT staff.staff_id, staff.firstname,
       (SELECT MAX(payment.amount) 
        FROM payment
        WHERE payment.staff_id = staff.staff_id)
FROM staff

我如何将此查询转换为子查询SQL

3 个答案: