Question

這個查詢中狄更斯錯在哪裏？

SELECT id, 
     SUM(CASE myDate 
      WHEN DATEDIFF(day, myDate, GETDATE()) = 0 THEN [Items] 
      ELSE 0 
      END) 
FROM myTable 
GROUP BY id 

???

錯誤說

"Incorrect syntax near '='. 

Answer 1

這是你想要的查詢：

SELECT id, 
     SUM(CASE WHEN DATEDIFF(day, myDate, GETDATE()) = 0 THEN [Items] ELSE 0 END) 
FROM myTable 
GROUP BY id; 

的myDate的case在做什麼你後。它在語法上允許的case語句的另一種形式：

sum(case mydate when '2013-01-01' then 'New Years Day' . . . 

但不是當你有when後的表達式。

Answer 2

你已經錯過了一個封閉的支架SUM(CASE myDate WHEN DATEDIFF(day, myDate, GETDATE()))我猜

Answer 3

你不需要的CASE

SELECT id, 
     SUM(CASE 
      WHEN DATEDIFF(day, myDate, GETDATE()) = 0 
      THEN [Items] ELSE 0 END) 

FROM myTable GROUP BY id; 

Answer 4

SELECT ID後mydate， SUM（CASE指明MyDate WHEN DATEDIFF（日，指明MyDate，GETDATE（）= 0），則[項目] ELSE 0 END） FROM mytable的 GROUP BY ID

這是正確的