MySQL查詢案例當30天，60天，而不是預定輸出

Question

我已經建立了下面的查詢嘗試&做到以下幾點：

1. 如果omSchedDate = 0〜30天今天則標誌「30天」
2. 如果omSchedDate = 31〜60天的今天則標誌‘60天’

3. 如果omSchedDate前一天0天或60天，然後後旗屬於‘未調度’

   SELECT DATEDIFF(tblcom.omSchedDate, CURDATE()) AS age, 
   
   CASE 
   WHEN tblcom.omSchedDate > CURDATE() AND tblcom.omSchedDate < (DATE_ADD(CURDATE(), 
   INTERVAL 31 DAY))THEN '30 Days' 
   WHEN DATEDIFF(CURDATE(), tblcom.omSchedDate) > 30 THEN '60 Days' 
   WHEN DATEDIFF(CURDATE(), tblcom.omSchedDate) <= 0 then 'Not Scheduled' 
   WHEN DATEDIFF(CURDATE(), tblcom.omSchedDate) IS NULL then 'Not Scheduled' 
   ELSE NULL 
   END AS consch 
   
   FROM  tblcom 
   ORDER BY tblcom.omSchedDate 
   

我上面的查詢爲30天列提供了正確的輸出，但「60天」&「未安排」列是不正確的？

Age, conSch 
-728,60 Days 
-726,60 Days 
-715,60 Days 
-666,60 Days 
-102,60 Days 
-88,60 Days 
-46,60 Days 
-15, 
-14, 
-5, 
-4, 
2,30 Days 
3,30 Days 
6,30 Days 
14,30 Days 
27,30 Days 
28,30 Days 
30,30 Days 
41,Not Scheduled 
41,Not Scheduled 
83,Not Scheduled 
188,Not Scheduled 

Answer 1

這裏有很多問題。首先，您的DATEDIFF操作中的減法順序相反。它應該是：

WHEN DATEDIFF(omSchedDate, CURDATE()) > 30 THEN '60 Days' 
WHEN DATEDIFF(omSchedDate, CURDATE()) < 0 THEN 'Not Scheduled' 

其次，你不必爲大於60天的差別的檢查，所以你需要補充的是，你需要檢查前，將其添加超過30天，否則大於60的值將永遠達不到該檢查。

WHEN DATEDIFF(omSchedDate, CURDATE()) > 60 THEN 'Not Scheduled' 

第三，如果omSchedDate都不可能是NULL（這是你的最後DATEDIFF行最終可能無效的唯一方法），那麼你真的應該檢查，首先，以防止可能出現的錯誤：

CASE 
WHEN omSchedDate IS NULL THEN 'Not Scheduled' 

，你還不如翻譯你的其他線路到DATEDIFF爲好，留給你：

CASE 
    WHEN omSchedDate IS NULL THEN 'Not Scheduled' 
    WHEN DATEDIFF(omSchedDate, CURDATE()) BETWEEN 0 AND 30 THEN '30 Days' 
    WHEN DATEDIFF(omSchedDate, CURDATE()) > 60 THEN 'Not Scheduled' 
    WHEN DATEDIFF(omSchedDate, CURDATE()) > 30 THEN '60 Days' 
    WHEN DATEDIFF(omSchedDate, CURDATE()) < 0 THEN 'Not Scheduled' 
    ELSE NULL 
END AS consch