Comma separated column values in sqlserver

If there is any requirement arieses we need to show comma separated column values eg:
Dummy values (Requirement)
abc,xyz,pqr etc.
Database column values
fields have an id
CatId CatName
1              abc
2              xyz
3              pqr

To achieve above requirement use following code:
DECLARE @Cat varchar(2000)Select @Cat = COALESCE(@Cat + ', ', '') + CAST(SubCategoryName AS varchar(200))FROM SubCategoryWHERE CategoryId=@CategoryIDReturn @Cat