string concatenate in group by function with other aggregate functions

Question

Is it possible to concatenate strings with one or more of other group by function like sum, avg, count etc .

Say I have the following table

Id Name O         


        

Answer 1

Sample table

create table t123 (Id int, Name varchar(10), [Order] int, Value int)
insert t123 select 
1,'a','1',100 union all select
2,'b','2',200 union all select
3,'c','1',300 union all select
4,'d','1',100 union all select
5,'e','2',300

Query for SQL Server 2005 and above

select a.[order], STUFF((
    select ','+b.name
    from t123 b
    where b.[order] = a.[order]
    order by b.name
    for xml path('a'), type).value('.','nvarchar(max)'),1,1,'') Name,
    SUM(a.value) value,
    COUNT(*) [count]
from t123 a
group by a.[order]

Output

order       Name         value       count
----------- ------------ ----------- -----------
1           a,c,d        500         3
2           b,e          500         2