Group By the position of the fieldname(column) in SQL Server
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I have a situation where in I have to concatenate two columns and group the selection based on the position of the field selected. Is this possible in SQL.

My sample code which doesn't execute. Here, GROUP BY 4 must group by the po_noRM

    SELECT Table_A.Po_no, Table_A.rmcode, SUM(Table_A.weight) as recvqty,
		LTRIM(RTRIM(Table_A.po_no)) + LTRIM(RTRIM(MBStran.rmcode)) as po_noRM
    FROM Table_A
    GROUP BY 4
    ORDER BY Table_A.Po_no
