How to concatenate columns separated by comma using sql xml.

Concatenate the Revision against soft

Soft	Revision
1	1
1	2
1	3
2	2
2	4
3	5

Select Soft , LEFT(Revision , LEN(Revision)-1) as Revision
FROM
(
Select Soft,
( Select Convert(VARCHAR,Revision)+',' from tblName x where x.soft= y.soft
for xml path('')
) as revision
from tblName y
group by soft
)ask

output

Soft	Revision
1	1,2,3
2	2,4
3	5