如何擴展SQL計算查詢以給出多個父行的結果

Question

以下查詢（針對教育應用）計算用戶對特定演練的分數。它適用於四個表格 - 用戶，演練，問題和答案。每個問題屬於演習，每個答案屬於一個問題和一個用戶（答案對用戶和問題是唯一的）。如果answer.selectedChoice = 1，問題是多項選擇並且答案是正確的。用戶的演練評分取決於該演練的最近五次答案，並且分配給正確答案的權重根據答案的速度縮放。

我想弄清楚如何擴展這個查詢，這樣，而不是僅僅得到一個特定鑽的用戶的分數，我可以得到每個鑽的用戶的分數，他們已經回答了至少一個問題。我一直在調查重寫它作爲相關的子查詢，但到目前爲止，我的努力已經不足。任何幫助將不勝感激。

SELECT data.*, 
    SUM(data.isCorrect * (IF(rawScore < 0, 0, IF(rawScore > 1, 1, rawScore))))/5 AS score 
FROM 
    (SELECT 
     answer.id, 
     IF(answer.selectedChoice = 1, 1, 0) AS isCorrect, 
     (1 - (answer.timeElapsed - question.baseTime)/(4 * question.baseTime)) as rawScore 
    FROM 
     answer, 
     question 
    WHERE 
     answer.questionID = question.id AND 
     question.drillID = :drillID AND 
     answer.userID = :userID 
    ORDER BY 
     answer.created DESC 
    LIMIT 
     5) as data 

Answer 1

請嘗試以下。假設「他們已經回答了至少一個問題」條件，您正在使用answer.created列。 這個想法是得到一個用戶的所有問題，並計算isCorrect，rawScore，得分（如果情況下）你需要的任何數據，並通過question.drillID，answer.userID（用戶的每個鑽頭的得分）分組，然後使用HAVING子句只獲得至少回答一個問題的用戶（他們至少回答了一個問題）。

下面的查詢可能會給你錯誤的結果 - 請張貼表結構和樣本數據，我可以爲你創建一個演示。

SELECT 
    answer.id, 
    IF(answer.selectedChoice = 1, 1, 0) AS isCorrect, 
    (1 - (answer.timeElapsed - question.baseTime)/(4 * question.baseTime)) as rawScore 
-- SUM(data.isCorrect * (IF(rawScore < 0, 0, IF(rawScore > 1, 1, rawScore))))/5 AS score 
-- SUM(IF(answer.selectedChoice = 1, 1, 0) * (IF(1 - (answer.timeElapsed - question.baseTime)/(4 * question.baseTime)) < 0, 0, IF((1 - (answer.timeElapsed - question.baseTime)/(4 * question.baseTime)) > 1, 1, (1 - (answer.timeElapsed - question.baseTime)/(4 * question.baseTime))))))/5 AS score 
FROM answer a 
INNER JOIN question q ON answer.questionID = question.id 
GROUP BY 
    question.drillID, answer.userID 
WHERE 
    answer.userID = :userID 
HAVING 
    COUNT(answer.created) >= 1;