How to concatenate strings in SQL Server, and sort/ order by a different column?

Question

I've seen many examples of concatenating strings in SQL Server, but if they worry about sorting, it's always by the column being concatenated. I need to order the values based on data in a different fields.

Sample table:

ClassID | StudentName   | SortOrder
-----------------------------
A       |James          |1
A       |Janice         |3
A       |Leonard        |2
B       |Luke           |2
B       |Leia           |1
B       |Artoo          |3

And the results I'd like to get are:

ClassID |StudentName
--------------------------------
A       |James, Leonard, Janice
B       |Leia, Luke, Artoo

How can this be done in SQL Server 2016? (I'm looking forward to STRING_AGG in 2017, but we're not there yet...)

Thanks!

Answer 1

Here you go:

SELECT
     s1.ClassID
   , STUFF((SELECT
                  ',' + s2.StudentName
            FROM  dbo.Student AS s2
            WHERE s1.classID = s2.ClassID
            ORDER BY s2.SortOrder
           FOR XML PATH('')), 1, 1, '') AS StudentNames
FROM dbo.Student AS s1
GROUP BY s1.ClassID

Answer 2

Here the query

IF OBJECT_ID('tempdb..#Temp') IS NOT NULL DROP TABLE #Temp;

CREATE TABLE #Temp(ClassId varchar(10),studName varchar(100),SortOrder int)

INSERT INTO #Temp(ClassId , studName, SortOrder)
SELECT 'A','James',1 UNION ALL
SELECT 'A','Janice',3UNION ALL
SELECT 'A','Leonard',2 UNION ALL
SELECT 'B','Luke',2 UNION ALL
SELECT 'B','Leia',1 UNION ALL
SELECT 'B','Artoo',3 


-- select * from #Temp

select
   distinct  
    stuff((
        select ',' + u.studName
        from #Temp u
        where u.studName = studName and U.ClassId =  L.ClassId
        order by u.SortOrder
        for xml path('')

    ),1,1,'') as userlist,ClassId
from #Temp  L
group by ClassId

Answer 3

SQL Fiddle

MS SQL Server 2017 Schema Setup :

CREATE TABLE MyTable(ClassID varchar(255),StudentName varchar(255),SortOrder int)
INSERT INTO MyTable(ClassID,StudentName,SortOrder)VALUES('A','James',1),('A','Janice',3),('A','Leonard',2),
                                                        ('B','Luke',2),('B','Lela',1),('B','Artoo',3)

Query 1 :

  SELECT
     t.ClassID
   , STUFF((SELECT
                  ',' + t1.StudentName
            FROM  MyTable t1
            WHERE t.classID = t1.ClassID
            ORDER BY t1.SortOrder
           FOR XML PATH('')), 1, 1, '') AS StudentNamesConcat
FROM MyTable AS t
GROUP BY t.ClassID

Results :

| ClassID |   StudentNamesConcat |
|---------|----------------------|
|       A | James,Leonard,Janice |
|       B |      Lela,Luke,Artoo |

Answer 4

You can try using PIVOT also. This will support even older version of SQL server. Only limitation : you should know the maximum SortOrder value. Below code will work for SortOrder <=20 of any ClassID

SELECT ClassID, ISNULL([1],'') +ISNULL(', '+[2],'')+ISNULL(', '+[3],'')+ISNULL(', '+ 
 [4],'')+ISNULL(', '+[5],'')+ISNULL(', '+[6],'')+ISNULL(', '+[7],'')+ISNULL(', '+ 
 [8],'')+ISNULL(', '+[9],'')+ISNULL(', '+[10],'')+ISNULL(', '+[11],'')+ISNULL(', '+ 
 [12],'')+ISNULL(', '+[13],'')+ISNULL(', '+[14],'')+ISNULL(', '+[15],'')+ISNULL(', '+ 
 [16],'')+ISNULL(', '+[17],'')+ISNULL(', '+[18],'')+ISNULL(', '+[19],'')+ISNULL(', '+ 
 [20],'') AS StudentName

FROM
(SELECT SortOrder,ClassID,StudentName 
FROM [Table1] A

) AS SourceTable
PIVOT
(
MAX(StudentName)
FOR SortOrder IN ([1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20])
) AS PivotTable