GROUP BY but get all values from other column

Question

I\'\'ll explain what I need to do on example. First of all, we have a simple table like this one, named table:

id | name
===+=====
1  | foo
1  | bar         


        

Answer 1

For SQL Server (before 2017) use FOR XML clause and STUFF() function for that:

SELECT distinct id, name = 
    STUFF((SELECT ' , ' + name
           FROM Table1 b 
           WHERE b.id = a.id 
          FOR XML PATH('')), 1, 2, '')
FROM Table1 a
GROUP BY id;

UPDATE

With SQL Server 2017, you can simply use STRING_AGG() function to achieve that:

SELECT ID, STRING_AGG (name, ', ') AS Name
FROM Table1
GROUP BY ID

See this SQLFiddle