SQL与多个计数来自同一列中选择

Question

我有一个表中的SQL有以下栏目：状态，CreateDateTime和案例类型

10行数据的示例如下所示：

Resolved-Withdrawn 2017-08-28 10:20:58.820 Termination Quote DE 
    Pending-Customer 2017-08-28 10:44:37.987 Termination Quote DE 
    Pending-Customer 2017-08-28 10:44:39.953 Termination Quote DE 
    Pending-Customer 2017-08-28 10:51:55.643 Termination Quote DE 
    Pending-Customer 2017-08-28 10:51:56.513 Termination Quote DE 
    Pending-Customer 2017-08-28 10:54:20.160 Termination Quote DE 
    Pending-Customer 2017-08-28 10:54:20.747 Termination Quote DE 
    Pending-Customer 2017-09-10 06:12:52.113 Termination Quote DE 
    Pending-Customer 2017-09-15 12:34:32.657 Termination Quote DE 

我想实现以下目标：

Status    Total_August  Total_September 
    ----------------------------------------------------- 
    Resolved-Withdrawn 1    0 
    Pending-Customer  6    2 

我将如何创建SQL中的这个查询？

我最初的想法是这样的（这显然是行不通的），但也许它可以让你更好的理解我的思维过程，作为一个非经验的用户。

SELECT Status, COUNT(pxCreateDateTime) as Total_August, COUNT(pxCreateDateTime) as Total_September 
    FROM ContractMgtWork 
    WHERE MONTH(pxCreateDateTime) = 8 and YEAR(pxCreateDateTime) = 2017 AND 
    CaseType = 'Amortization Schedule DE' 
    GROUP BY Status 

Answer 1

count，像许多其他聚合函数，跳过null秒。您可以通过计数case表达任何你想利用这个属性来计算：

SELECT Status, 
     COUNT(CASE WHEN MONTH(pxCreateDateTime) = 8 THEN 1 END) AS Total_August, 
     COUNT(CASE WHEN MONTH(pxCreateDateTime) = 9 THEN 1 END) AS Total_September 
FROM  ContractMgtWork 
WHERE YEAR(pxCreateDateTime) = 2017 AND 
     CaseType = 'Amortization Schedule DE' 
GROUP BY Status