Question

我有包含开始和结束日期记录的表，因此我必须获取从星期五开始的所有记录，如果星期五是假期，则获取星期四；如果星期五和星期四是假期，则获取星期三，依此类推上...

目前我有两个表TableA用于记录，Calendar用于休假。

我的TableA看起来像这样：

id beg         end
--------------------------
1  11/01/2019  14/01/2019
2  10/01/2019  14/01/2019
3  09/01/2019  15/01/2019
...

日历看起来像这样：

iddate    date        weekday isholiday
---------------------------------------
20190109  09/01/2019  3       0 --0=False / 1=True
20190110  10/01/2019  4       0
20190111  11/01/2019  5       1
...

对于两个表，我都使用WHERE EXISTS来获取星期五和实际显示结果的假期条件：

SELECT *
FROM TableA t
WHERE EXISTS (SELECT 1
              FROM dbo.Calendar AS c
              WHERE c.date = CAST(t.BEG AS DATETIME)
                AND c.weekday = CASE
                                    WHEN (C.weekday = 5 AND C.isholiday = 0)  
                                       THEN 5 --keep friday
                                    --WHEN ((C.weekday= 4 AND C.isholiday= 1) OR (C.weekday= 5 AND C.isholiday= 1)) THEN 3 --keep wednesday / not working
                                       ELSE 4 --keep thursday
                                    END
                AND DATEPART(yyyy, T.beg) = 2019)
ORDER BY 
    CAST(INI AS [datetime])

如果星期五是假期，它将显示以下内容：

id beg         end
--------------------------
2  10/01/2019  14/01/2019
3  09/01/2019  15/01/2019

如果星期五和星期四为节假日，则应显示：

id beg         end
--------------------------
3  09/01/2019  15/01/2019

使用此WHEN ((C.weekday= 4 AND C.isholiday= 1) OR (C.weekday= 5 AND C.isholiday= 1))进行扩展只会破坏整个查询，并且我得到-几乎是随机的日期。有没有扩大查询范围的任何方法？

Answer 1

根据您的评论，我将使用一个常见的表表达式：

;With cte_Last_Day_Of_Week
As
(
    Select 
        c.iddate
        , c.date
        , Row_Number() Over (Partition By DatePart(Week, c.date) Order By c.date Desc) As RN
    From dbo.Calendar As c
    Where c.isholiday = 0
)

Row_Number()将用1的值标记每个星期中最后一个非节假日的日期。然后，您可以像桌子一样加入。

让我知道这是否合理。

缩放CASE WHEN来检索非假日日期

1 个答案: