Question

我必须创建一个查询，为多个表中的每个玩家（用户）编译一堆数据。例如，我有两个表： tblMembers 和 Off_Ice_Testing 。

每个tblMembers（或没有）有多个off_ice_testing。如何选择一个具有最新日期的off_ice_testing？

我试过了：

   SELECT m.LastName, 
          m.FirstName, 
          office.Date AS [off ice date]
   FROM tblMembers AS m 
   LEFT JOIN (SELECT Date, UserID
              FROM Off_Ice_Testing) AS office ON m.UserID = office.UserID
   WHERE m.LastName LIKE '%player%'

但是，这会为每个 Off_ice_Testing 取回记录。如果我在派生表中执行 Top（1），那将无效。我觉得我应该知道这一点，但我被困住了。为了将来参考，您会将这种类型的查询称为什么？

Answer 1

SELECT m.LastName, m.FirstName, o.[Date] AS [off ice date]
FROM tblMembers AS m
LEFT JOIN 
(
  SELECT UserID, MAX([Date]) as [Date] FROM Off_Ice_Testing
  GROUP BY UserID
)o ON (o.UserID = m.UserID)
WHERE     (m.LastName LIKE '%player%')

SQL查询多个表/记录

1 个答案: