使用SUM函數

Question

內布爾邏輯在SQL Server 2008中，這個查詢的工作原理：

SELECT 
    SUM(CAST(isredeemed AS TINYINT)) AS totalredeemed, 
FROM rewards 
GROUP BY merchantid 

它給你的商家兌換獎勵的數量。劇組需要避免出現錯誤Operand data type bit is invalid for sum operator.

現在我想要做一個類似的查詢，但是隻能找到在過去幾天內獲得的獎勵。我嘗試這樣做：

SELECT 
    SUM(CAST((isredeemed & (MIN(dateredeemed) > '2014-01-10 05:00:00')) AS TINYINT)) AS claimedthisweek, 
FROM rewards 
GROUP BY merchantid 

，我得到的錯誤

附近有語法錯誤 '>'。

我也試圖與&&並與AND更換&。但那些也不起作用。

如何讓示例工作？

Answer 1

這個問題缺乏詳細給出一個確切的答案，但你需要使用一個派生表或子查詢的計算。

像這樣

SELECT r1.merchantid, r2.claimedthisweek 
FROM rewards r1 
JOIN (
    SELECT merchantid, SUM(CAST(isredeemed AS INT)) claimedthisweek 
    FROM rewards 
    GROUP BY merchantid 
    HAVING MIN(dateredeemed) > '20140101' 
) r2 

Answer 2

我想你想這會工作，但它只能算作有些兩次：

SELECT 
    SUM(case when MIN(dateredeemed) > '2014-01-10 05:00:00' then 1 else 0 end)  
FROM rewards 
GROUP BY merchantid 

Answer 3

這應該是having子句上，像這樣：

SELECT 
    SUM(CAST((isredeemed AS TINYINT)) AS claimedthisweek 
    FROM rewards 
    GROUP BY merchantid 
    HAVING MIN(dateredeemed) > '2014-01-10 05:00:00' 

Answer 4

任何理由不這樣做濾波在「where」子句級別？這應該工作，只要你符合聚合在同一條件的所有行：

SELECT 
    SUM(CAST(isredeemed AS TINYINT)) AS claimedthisweek 
FROM rewards 
WHERE dateredeemed > '2014-01-10 05:00:00' 
GROUP BY merchantid