SQL Query to get aggregated result in comma separators along with group by column in SQL Server

You want to use FOR XML PATH construct:

select 
    ID, 
    stuff((select ', ' + Value 
           from YourTable t2 where t1.ID = t2.ID 
           for xml path('')),
          1,2,'') [Values]
from YourTable t1
group by ID

The STUFF function is to get rid of the leading ', '.

You can also see another examples here:

• SQL same unit between two tables needs order numbers in 1 cell
• SQL and Coldfusion left join tables getting duplicate results as a list in one column