MYSQL将连接转换为子查询

Question

我尝试将连接查询转换为不具有连接并仅使用子查询，但对于我的生活，我无法找到方法。

TABLES：

使用这些表格，我尝试执行以下操作：使用子查询获取支付最多注册的与会者的FirstName，LastName和注册费用。

此查询使用连接生成该结果。

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

有办法做到这一点吗？感谢。

Answer 1

这应该有效：

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