mysql'case'具有多個'WHEN'值

Question

我有一個查詢需要對其他2列爲真的列進行計數。 當'DealerName'像'％MINI％'和'DealerContact_Y'= 1時，我需要計算'DealerName''

但我不確定語法。此查詢產生錯誤

SELECT DealerName, 
     count(DealerShipId) as dealersContacted, 
     CASE WHEN 
     DealerName LIKE "%MINI%", WHEN DealerContact_Y = 1 
     THEN Count(DealerContact_Y) END as Mini_contacted_yes, 
     Campaign, 
     DealerId 
     FROM tblsummaryResults 

是否有辦法在case語句中執行多個WHENS？

Answer 1

你會使用DealerName LIKE '%MINI%' AND DealerContact_Y = 1這樣寫：

SELECT DealerName, 
    count(DealerShipId) as dealersContacted, 
    count(CASE 
      WHEN DealerName LIKE '%MINI%' 
       AND DealerContact_Y = 1 
      THEN DealerContact_Y END) as Mini_contacted_yes, 
    Campaign, 
    DealerId 
FROM tblsummaryResults 

Answer 2

所以，做這樣的計數：

COUNT(
    IF(DealerName LIKE "%MINI%" AND DealerContact_Y = 1, DealerContact_Y, NULL) 
) AS Mini_contacted_yes