如何在MySQL中對多個子查詢進行分組

Question

嗨我正在嘗試對一系列子查詢進行分組，但不斷爲每行獲得相同的結果。

 SELECT Campaign_Name, 
        (SELECT COUNT(Bounce) 
        FROM `temp_Data`) AS Sent, (SELECT COUNT(Bounce) 
              FROM `temp_Data` 
              WHERE Bounce = '0') AS Delivered, (SELECT SUM(Opened) 
                 FROM `temp_Data` 
                 WHERE Opened = '1')AS Opened 
FROM temp_Data 

GROUP BY Campaign_Name 

結果是：

Campaign Name Sent Delivered Opened 
Campaign1  300 278  196 
Campaign2  300 278  196 

我的數據是0.1所以，即使我總結它仍然給了我同樣的結果。

如何獲得每個廣告系列的個人計數？

Answer 1

這可以在一個單一的查詢

SELECT 
    Campaign_Name, 
    COUNT(*) AS Sent, 
    COUNT(CASE WHEN Bounce = '0' THEN 1 ELSE NULL END) AS Delivered, 
    COUNT(CASE WHEN Opened = '1' THEN 1 ELSE NULL END) AS Opened 
FROM temp_Data 
GROUP BY Campaign_Name 

做看看control functions和COUNT。

棘手的部分是COUNT不增加NULL值，所以我用它來做一個選擇性計數。