multiple row data from database into single row in gridview

You can use XML PATH to do it.

Try like this,

SELECT p1.StaffName, p1.Role
( SELECT GroupNumber + ', '
FROM YourTable p2
WHERE p2.ID = p1.ID
ORDER BY GroupNumber
FOR XML PATH('') ) AS GroupNumber
FROM YourTable p1
GROUP BY p1.StaffName, p1.Role;