根据参数和最后一行日期更新临时 table 中的日期

Question

我正在尝试使用参数并查看最后一行编号的日期来更新临时 table 中的日期。

DECLARE @multiDayCourseDaysBetween INT = 3;

CREATE TABLE #Courses(TempId INT IDENTITY(1,1)
                        , [Date] DATE
                        , CourseTypeId INT
                        , OrganisationId INT
                        , Reference VARCHAR(100)
                        , CreatedByUserId INT
                        , CourseTypeCategoryId INT
                        , TrainersRequired INT);

CREATE TABLE #TempDates(TempId INT
                        , [Date] DATE
                        , LagDate DATE);

INSERT INTO #Courses([Date])
Values('2016-06-01')

INSERT INTO #Courses([Date])
Values('2016-06-02')

INSERT INTO #Courses([Date])
Values('2016-06-03')

INSERT INTO #TempDates(tempId, [date], LagDate)
SELECT TempId, [Date]  
     , LAG(c.[Date],1) OVER (ORDER BY [Date]) as LagDate
FROM #Courses c

UPDATE #TempDates
SET [Date] = DATEADD(dd, @multiDayCourseDaysBetween, LAG([Date],1) OVER (ORDER BY [Date])) 
WHERE LagDate IS NOT NULL

但是我收到一个错误 - 'Windowed functions can only appear in the SELECT or ORDER BY clauses.'

例如，原始日期为

2016-06-01
2016-06-02
2016-06-03

但我需要他们成为

2016-06-01
2016-06-04
2016-06-07

基于 3 作为参数。

感谢您的帮助

Answer 1

尝试将最后一条语句更改为如下内容：

WITH b AS (
SELECT
    TempId
    , [Date]
    , FIRST_VALUE([Date]) OVER (ORDER BY [Date]) as FirstDate
    , ROW_NUMBER() OVER (ORDER BY [Date]) AS rowRank
FROM
    #TempDates
)
UPDATE b
SET [Date] = DATEADD(day, (rowRank-1)* @multiDayCourseDaysBetween, FirstDate)
WHERE
    rowRank > 1;

根据参数和最后一行日期更新临时 table 中的日期

Update date in temporary table based upon parameter and last row date

tsql

lag