Question

我正在尝试编写一个产生两列的查询：月和计数

Month      COUNT
Jan 2018    563
Feb 2018    701
Mar 2018    682
Apr 2018    596
May 2018    395
Jun 2018    538

但是我得到的结果是：

Jan 2018    Feb 2018    Mar 2018    Apr 2018    May 2018    Jun 2018
   563        701         682         596         395          538

很显然，我的查询需要调整。

我尝试使用数据透视功能，但是它太复杂了，所以我想知道是否存在另一种方式编写查询以获取所需格式。

这是我当前的查询：

SELECT

,SUM(CASE WHEN DateRequest BETWEEN '2018-01-01' AND '2018-01-31' THEN 1 ELSE 0 END) as 'Jan 2018'
,SUM(CASE WHEN DateRequest BETWEEN '2018-02-01' AND '2018-02-28' THEN 1 ELSE 0 END) as 'Feb 2018'
,SUM(CASE WHEN DateRequest BETWEEN '2018-03-01' AND '2018-03-31' THEN 1 ELSE 0 END) as 'Mar 2018'
,SUM(CASE WHEN DateRequest BETWEEN '2018-04-01' AND '2018-04-30' THEN 1 ELSE 0 END) as 'Apr 2018'
,SUM(CASE WHEN DateRequest BETWEEN '2018-05-01' AND '2018-05-31' THEN 1 ELSE 0 END) as 'May 2018'
,SUM(CASE WHEN DateRequest BETWEEN '2018-06-01' AND '2018-06-30' THEN 1 ELSE 0 END) as 'Jun 2018'

FROM RequestHeader

感谢您的帮助。谢谢。

Answer 1

具有一个派生表，您可以在其中提取年和月部分。 GROUP BY其结果：

select m, y, count(*)
from
(
    select month(DateRequest) as m, year(DateRequest) as y
    from tablename
) dt
group by m, y

如果您的dbms不支持month()和year()函数，请尝试使用ANSI SQL的EXTRACT(MONTH FROM DateRequest)和EXTRACT(YEAR FROM DateRequest)。

Answer 2

您的代码建议使用SQL Server语法，所以我会尝试：

WITH CTE AS (
     <query>
)
SELECT CC.*
FROM CTE C CROSS APPLY
     ( VALUES ('Jan 2018', [Jan 2018]), 
              ('Feb 2018', [Feb 2018]),
                . . . 
     ) CC(mn, cnt);

是否可以不使用数据透视功能来透视桌子？

2 个答案: