在 string_agg 中排序似乎不起作用

order by in string_agg does not seems to work

我有一个 table #tmp 是这样的:

recid       DefaultDimension    DefaultDimensionName    line_no
5637423499  Default             Employee                7
5637423499  1001                Product                 8
5637423499  100                 Region                  2
5637423499  1                   Routing                 17
5637423499  115                 Section                 5
5637423499  999                 Unit                    6
5637423499  1510                Branch                  3
5637423499  A                   CabinClass              14
5637423499  0B                  Carrier_Property        9
5637423499  103                 Channel                 16
5637423499  104                 Department              4
5637423499  113                 Division_CustomerType   1

我想根据 line_no

的升序连接 DefaultDimension 和 DefaultDimensionName 列

这是我写的查询,但我没有按顺序得到它:

select recid, 
STRING_AGG(DefaultDimension, '-')  WITHIN GROUP (ORDER BY line_no ASC) DefaultDimension,
STRING_AGG(DefaultDimensionName, '-') WITHIN GROUP (ORDER BY line_no ASC) DefaultDimensionName 
from #tmp
group by recid

结果:

recid       DefaultDimension                                    DefaultDimensionName
5637423499  113-A-103-1-100-1510-104-115-999-Default-1001-0B    Division_CustomerType-CabinClass-Channel-Routing-Region-Branch-Department-Section-Unit-Employee-Product-Carrier_Property

如您所见,CabinClass 应该排在倒数第三位,但它排在第二位。

因为你的 line_no 好像是 varchar,先把它转换成 INT:

select recid, 
       STRING_AGG(DefaultDimension, '-')  WITHIN GROUP (ORDER BY cast(line_no as INT) ASC) DefaultDimension,
       STRING_AGG(DefaultDimensionName, '-') WITHIN GROUP (ORDER BY cast(line_no as INT) ASC) DefaultDimensionName 
from #tmp
group by recid

您的 line_novarchar,您通常会注意到

'1' < '14' < '16 < '17' < '2'

所以,只要简单地将varchar解析成int就解决了问题。

select recid, 
STRING_AGG(DefaultDimension, '-')  WITHIN GROUP (ORDER BY CAST(line_no AS int) ASC) DefaultDimension,
STRING_AGG(DefaultDimensionName, '-') WITHIN GROUP (ORDER BY CAST(line_no AS int)ASC) DefaultDimensionName 
from #tmp
group by recid