Hi Maryam.
If you want to sum your col2, col3, coln values while grouping by col1, you can you COLLECT statement.
Take a look at this:
http://help.sap.com/saphelp_nw2004s/helpdata/en/fc/eb36d5358411d1829f0000e829fbfe/content.htm
It will do exactly what you want.