Question

在SQL Server 2008中，此查询有效：

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

它为您提供商家兑换奖励的数量。 TINYINT强制转换需要避免错误Operand data type bit is invalid for sum operator.

现在我想做一个类似的查询，但只能查找过去几天兑换的奖励。我试过这个：

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

我收到了错误

'＆gt;'附近的语法不正确。

我还尝试用&和&&替换AND。但那些也不起作用。

如何使示例有效？

Answer 1

这个问题缺乏细节来给出确切的答案，但您需要使用派生表或子查询进行计算。

类似这样的事情

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

我认为你希望这会有效，但它会算两次：

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

Answer 3

这应该在having子句上，如下所示：

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

Answer 4

有什么理由不在“where”子句级别进行过滤？只要您聚合的所有行都符合相同的条件，这应该有效：

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

在SUM函数中使用布尔逻辑

4 个答案: