[我尝试查找所有在2018年期间每月至少有一天会员资格的Cust。我想出了一种在每个月初/中/月末检查其会员资格的解决方案,如下面的代码段所示,但尝试查找更多智能解决方案。
我知道我可以在365天的每一天内使用计数表进行检查,但是可能有更优雅的解决方案?我对SQL有点陌生,我认为我在GROUPING区域中缺少某些内容。
在下面显示的代码段中,两个Cust都有至少一天的会员资格。全部发送。
所需的输出:
CustID
------
1
22
代码:
with data as
(
select *
from (values (1, 1, '2017-12-11', '2018-01-16'), (1, 22, '2018-01-28', '2018-03-9' ), (1, 333, '2018-03-1', '2018-12-31') , -- island
(22, 1, '2017-12-31', '2018-01-11'), (22, 2, '2017-2-11', '2019-12-31')) as t (CustID, ContractID, StartDD, EndDD) ---
)
select
isdate(startDD), isdate(EndDD)
from
data
), gaps as
(
select
*,
datediff(day, lag(EndDD, 1, StartDD) over (partition by CustID order by StartDD), StartDD) as BreakDD -- negative is island
from
data
)
select
*,
datepart(month,StartDD) mmS , datepart(month,EndDD) mmE
from
gaps
-- and was active any 1+ day during each of the 12 months in 2018 ????
where
1 = 1
/* and (cast('1/1/2018' as date) between StartDD and EndDD
or cast('1/15/2018' as date) between StartDD and EndDD
or cast('1/31/2018' as date) between StartDD and EndDD)
---- etc.. for each month
and ( cast('12/1/2018' as date) between StartDD and EndDD
or cast('12/15/2018' as date) between StartDD and EndDD
or cast('12/31/2018' as date) between StartDD and EndDD
)
*/
--select CustID, max(BreakDD) Max_Days
--from gaps
--group by CustID
首先创建一个函数,以返回给定日期之间的所有月份和年份。
功能:
--SELECT * FROM dbo.Fn_GetMonthYear('2017-12-11','2018-01-16')
ALTER FUNCTION dbo.Fn_GetMonthYear(@StartDate DATETIME,@EndDate DATETIME)
RETURNS TABLE
AS
RETURN(
SELECT DATEPART(MONTH, DATEADD(MONTH, x.number, @StartDate)) AS [Month]
,DATEPART(YEAR, DATEADD(MONTH, x.number, @StartDate)) AS [Year]
FROM master.dbo.spt_values x
WHERE x.type = 'P'
AND x.number <= DATEDIFF(MONTH, @StartDate, @EndDate)
)
表模式:
CREATE TABLE #t(CustID INT, ContractID INT, StartDD date, EndDD date)
INSERT INTO #t values (1, 1, '2017-12-11', '2018-01-16'), (1, 22, '2018-01-28', '2018-03-9' ), (1, 333, '2018-03-1', '2018-12-31') , -- island
(22, 1, '2017-12-31', '2018-01-11'), (22, 2, '2017-2-11', '2019-12-31')
这是您的要求的。T-SQL查询
SELECT CustID
,COUNT(DISTINCT [Month]) NoOfMonths
FROM(
SELECT *
FROM #t t
CROSS APPLY dbo.Fn_GetMonthYear(StartDD,EndDD)
)D
WHERE [Year] = 2018
GROUP BY CustID
HAVING COUNT(DISTINCT [Month])=12
结果:
CustID NoOfMonths
1 12
22 12