使用CTE

Question

我必须在Microsoft SQL Server中为一年中的两个代码之间交替分配一个特定房间的颜色代码。唯一字段是日历的每个日期。

因此示例行如下所示。

weekDay       colorName   RoomNum
2017-01-01    Blue        100
2017-01-02    Red         100

每周需要分配颜色代码，从星期一（本周开始）到星期日的2种颜色之间交替计算为星期结束。所以从2017年1月2日星期一开始，我需要以下模式继续下一个日历年，所以到2018年底。

2017-01-02    Red         100
2017-01-03    Red         100
2017-01-04    Red         100 
2017-01-05    Red         100
2017-01-06    Red         100
2017-01-07    Red         100
2017-01-08    Red         100
2017-01-09    Blue        100
2017-01-10    Blue        100
2017-01-11    Blue        100 
2017-01-12    Blue        100
2017-01-13    Blue        100
2017-01-14    Blue        100
2017-01-15    Blue        100
2017-01-16    Red         100
.
.
.

我有以下CTE，但它在第一周分配6天，然后每周分配14天，而不是每周一至周日开始七天。我究竟做错了什么？谢谢！

DECLARE @tableTest TABLE (weekDay datetime, colorName varchar(50), roomNum int);

DEClARE @begindate datetime = '01/02/17';
declare @enddate datetime = '12/31/18';

;with 
 N0 as (SELECT 1 as n UNION ALL SELECT 1)
,N1 as (SELECT 1 as n FROM N0 t1, N0 t2)
,N2 as (SELECT 1 as n FROM N1 t1, N1 t2)
,N3 as (SELECT 1 as n FROM N2 t1, N2 t2)
,N4 as (SELECT 1 as n FROM N3 t1, N3 t2)
,N5 as (SELECT 1 as n FROM N4 t1, N4 t2)
,N6 as (SELECT 1 as n FROM N5 t1, N5 t2)

,nums as (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 1)) as num FROM N6)
INSERT @tableTest (weekDay, roomNum)
SELECT DATEADD(day,num-1,@begindate) as thedate, 100
FROM nums
WHERE num <= DATEDIFF(day,@begindate,@enddate) + 1

;with weekNumber as (
SELECT weekDay, colorName, roomNum, (DATEPART(ww, weekDay) / 2) % 2  as schedule FROM @tableTest
)
UPDATE weekNumber
SET colorName = CASE WHEN weekNumber.schedule = 0  THEN 'Red' ELSE 'Blue' END

SELECT * FROM @tableTest

Answer 1

你正在进行分割和模数运算，这会导致你加宽＆＃34;宽度＆＃34;模数，如果这个术语对你有意义。 ：）

换句话说，而不是对1,2,3,4等模数进行模数。

你对1,1.5,2,2.5,3等做模数。得到它吗？

无论如何，解决方案是将最终更新更改为：

;with weekNumber as (
SELECT weekDay, colorName, roomNum, (DATEPART(ww, weekDay)) % 2  as schedule FROM @tableTest
)
UPDATE weekNumber
SET colorName = CASE WHEN weekNumber.schedule = 0  THEN 'Red' ELSE 'Blue' END