select distinct one column with all instances of another column in a second column If I have a table with the following information:  

ParentID | ChildID
---------+--------
     6   |      6 
     6   |      7 
     6   |      8 
     6   |      9 
     6   |     10 


I need to display the distinct parent with all instances of child in the second column possibly concatonated with a comma e.g.  

ParentID | ChildID
---------+--------
   6     |     6, 7, 8, 9, 10


Thanks in advance!
You can use a pattern like this:

SELECT files.database_id, db.name AS DatabaseName,
        STUFF((SELECT ', ' + names.name
                FROM sys.master_files names
                WHERE names.database_id = files.database_id
                FOR XML PATH(''),TYPE).value('.','VARCHAR(MAX)')
            , 1, 2, '') AS NameList
FROM sys.master_files files
JOIN sys.databases db
    ON files.database_id = db.database_id
GROUP BY files.database_id, db.name