SQL 服务器使用 SUM 连接到新列

Question

Please consider the following sample data:

Part Loc Qty
A A-1 10
A A-5 15
A B-4 7
B B-5 10
B B-6 15

I can query easily enough to get the location qty for each part:

select
    pt.Part
    ,lc.Loc
    ,lc.LocQty Qty
from
    Part pt
left join
    Loc lc
on
    pt.Part = lc.Part

I can also sum the locations like so:

select
    pt.Part
    ,sum(lc.LocQty) TotalQty
from
    Part pt
left join
    Loc lc
on
    pt.Part = lc.Part
group by
    pt.Part

What I want to do now is instead concatenate into a new column, each location that the part appears, like so:

Part TotalQty InLocations
A 32 A-1, A-5, B-4
B 25 B-5, B-6

What would be the best approach to this?

Many thanks

Answer 1

SQL SERVER replacement of GROUP_CONCAT() is STRING_AGG() .But STRING_AGG() was introduced in SQL Server 2017 version, you have to use combination of STUFF and For XML PATH to get your result.

SELECT P.PART,SUM(QTY) AS TOTALQTY,
       INLOCATIONS = STUFF(
                     (
                      SELECT ', ' + PA.LOC 
                      FROM PART AS PA 
                      WHERE PA.PART = P.PART
                      FOR XML PATH('')
                     ), 1, 2, N''
                     ) 
 FROM PART P
 GROUP BY P.PART

Check Demo here