將日期納入此GROUP BY和INNER JOIN select語句

我試圖在我的獎勵系統中列出前20名收入者。將日期納入此GROUP BY和INNER JOIN select語句

下面的語句完美的作品表明：

SELECT 
    S.User_ID As UserID, 
    CONCAT(S.User_Forename, " ", S.User_Surname) AS StudentName, 
    T.TotalPoints 
FROM 
    student S 
INNER JOIN 
    (SELECT 
     Datetime, Recipient_ID, SUM(Points) AS TotalPoints 
     FROM 
     transactions 
     GROUP BY 
     Recipient_ID) T 
ON 
    S.User_ID = T.Recipient_ID 
ORDER BY TotalPoints DESC 
LIMIT 20

來然而，想起來了，明年我需要包括日期範圍（即顯示收入最高的那所學校一年只）。

出於測試目的，我試圖修改下面的語句，其中包括一個LESS THAN DATETIME選擇：

SELECT 
    S.User_ID As UserID, 
    CONCAT(S.User_Forename, " ", S.User_Surname) AS StudentName, 
    T.TotalPoints 
FROM 
    student S 
INNER JOIN 
    (SELECT 
     Datetime, Recipient_ID, SUM(Points) AS TotalPoints 
     FROM 
     transactions 
     GROUP BY 
     Recipient_ID) T 
ON 
    S.User_ID = T.Recipient_ID 
WHERE t.Datetime < 2012-03-20 
ORDER BY TotalPoints DESC 
LIMIT 20

我也試過這樣：

SELECT 
    S.User_ID As UserID, 
    CONCAT(S.User_Forename, " ", S.User_Surname) AS StudentName, 
    T.TotalPoints 
FROM 
    student S 
INNER JOIN 
    (SELECT 
     Datetime, Recipient_ID, SUM(Points) AS TotalPoints 
     FROM 
     transactions 
     WHERE Datetime < 2012-03-20 
     GROUP BY 
     Recipient_ID) T 
ON 
    S.User_ID = T.Recipient_ID 
ORDER BY TotalPoints DESC 
LIMIT 20

這兩項的但顯示空結果集。

如果我做了一個簡單的SELECT * FROM transactions WHERE Datetime < 2012-03-20，返回25K以上的結果。

我哪裏錯了？

來源

2012-07-09 dunc

你嘗試在你的日期值一個單引號？ '2012-03-20' – Taryn 2012-07-09 15:43:19

我很好奇。也許我錯過了一些東西，但是日期時間不在聚合或組合語句中。它在T子查詢中會發生什麼？ – 2012-07-09 15:44:45

@dunc嘗試bluefeet的建議。它應該工作。 – 2012-07-09 15:47:03

看來，你缺少的單引號'在你的日期值：

WHERE t.Datetime < '2012-03-20'

來源

2012-07-09 15:50:32 Taryn

將日期納入此GROUP BY和INNER JOIN select語句

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