更新时间:2023-01-28 21:54:37
原始问题文本与ISO_WEEK编号的一个简单格式问题有关,但是我认为与今年的串联有关的问题更大简单地将DatePart YYYY和ISO_WEEK串联会在第1周和/或第53周的几天中产生错误的(或至少是意外的)结果,尤其是像2014-12-31这样的日期是第1周的一部分,而不是2014-W01。同样,2016-01-01将成为2015-W53的一部分,而不是2016-W53。为了确定Iso Yea r-Week年份必须更正以考虑到这一点:
The original question text relates to a simple formatting issue of the ISO_WEEK number, but I feel there is a bigger issue here with the concatenation of the year part. Simply concatenating DatePart YYYY and ISO_WEEK will yield incorrect (or at least unexpected) results for days in week 1 and/or 53. Notably dates like 2014-12-31 are part of week 1, but not 2014-W01. It is part of 2015-W01. Similarly, 2016-01-01 will be part of 2015-W53, not 2016-W53. In order to determine the Iso Year-Week the year must be corrected to take this into account:
With
Dates (Date) As (
Select Convert( date, N'2014-12-31' )
Union All Select Convert( date, N'2015-01-01' )
Union All Select Convert( date, N'2015-12-31' )
Union All Select Convert( date, N'2016-01-01' )
)
Select
src.Date
, Concat( Case
When DatePart( Month, src.Date ) = 12 And DatePart( ISO_WEEK, src.Date ) = 1 Then DatePart( Year, src.Date ) + 1
When DatePart( Month, src.Date ) = 1 And DatePart( ISO_WEEK, src.Date ) > 50 Then DatePart( Year, src.Date ) - 1
Else DatePart( Year, src.Date )
End, N'-W', Right( Concat( N'00', DatePart( ISO_WEEK, src.Date ) ), 2 ) ) As IsoYearWeek
From
Dates src
;