使用SUM函数

Question

内布尔逻辑在SQL Server 2008中，这个查询的工作原理：

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

它给你的商家兑换奖励的数量。剧组需要避免出现错误Operand data type bit is invalid for sum operator.

现在我想要做一个类似的查询，但是只能找到在过去几天内获得的奖励。我尝试这样做：

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

，我得到的错误

附近有语法错误 '>'。

我也试图与&&并与AND更换&。但那些也不起作用。

如何让示例工作？

Answer 1

这个问题缺乏详细给出一个确切的答案，但你需要使用一个派生表或子查询的计算。

像这样

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

我想你想这会工作，但它只能算作有些两次：

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

Answer 3

这应该是having子句上，像这样：

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

Answer 4

任何理由不这样做滤波在“where”子句级别？这应该工作，只要你符合聚合在同一条件的所有行：

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