多個表/記錄的SQL查詢

Question

我必須創建一個查詢，爲多個表中的每個玩家（用戶）編譯一堆數據。例如，我有兩個表格：tblMembers和Off_Ice_Testing。

每個tblMembers（或沒有）有多個off_ice_testing。如何選擇一個具有最新日期的off_ice_testing？

我想：

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%' 

但是回來每個Off_ice_Testing的記錄。如果我在派生表中執行頂部（1），那不起作用。我覺得我應該知道這一點，但我卡住了。而爲了將來的參考，你會稱這種類型的查詢？

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%')