MYSQL将联接转换为子查询

Question

我试图将联接查询转换为不具有联接，而仅使用子查询，但是对我而言，我不知道一种方法。

表格：

使用这些表，我尝试执行以下操作：使用子查询获取注册费用最高的与会者的名字，姓氏和注册费用。

该查询使用联接产生该结果。

SELECT FirstName, LastName, SUM(tblregistration.RegistrationPaid) AS `AmountPaid`
FROM tblregistration, tblattendees
WHERE tblregistration.AttendeeID = tblattendees.AttendeeID
GROUP BY tblregistration.AttendeeID 
ORDER BY `AmountPaid` DESC 
LIMIT 5

有没有办法做到这一点？ 谢谢。

Answer 1

这应该工作：

SELECT
  (SELECT FirstName FROM tblattendees WHERE tblregistration.AttendeeID = tblattendees.AttendeeID) AS `FirstName`,
  (SELECT LastName FROM tblattendees WHERE tblregistration.AttendeeID = tblattendees.AttendeeID) AS `LastName`,
  SUM(tblregistration.RegistrationPaid) AS `AmountPaid`
FROM tblregistration
GROUP BY tblregistration.AttendeeID
ORDER BY `AmountPaid` DESC
LIMIT 5