How to add Alias column as generated new coloumn

ALTER PROCEDURE [dbo].[rptrm_pm_stck_summary]
@frmdate date,
@todate date
AS
BEGIN

select item_code,(select item_desc from tblItemMaster where cs.item_code=item_code)as item_desc,(select UOM from tblItemMaster where cs.item_code=item_code)as UOM,batch_no,
opening_qty
,(select SUM(receipt_qty) from tblGRNEntry where GRN_Date between @frmdate and @todate and cs.item_code=item_code and cs.batch_no=batch_no) as receipt_qty,(select SUM(issue_qty) from tblMINDateEntry where MIN_Date between @frmdate and @todate and cs.item_code=item_code and cs.batch_no=batch_no) as issue_qty,
(select SUM(Qty) from tblStockAdjustment where Ref_Date between @frmdate and @todate and cs.item_code=item_code and cs.batch_no=batch_no) as ads_qty

--,(opening_qty+(select SUM(receipt_qty) from tblGRNEntry where GRN_Date between @frmdate and @todate and cs.item_code=item_code and cs.batch_no=batch_no)-(select SUM(issue_qty) from tblMINDateEntry where MIN_Date between @frmdate and @todate and cs.item_code=item_code and cs.batch_no=batch_no)+(select SUM(Qty) from tblStockAdjustment where Ref_Date between @frmdate and @todate and cs.item_code=item_code and cs.batch_no=batch_no))  


 from tblClosingStock cs
where
adddate between @frmdate and @todate
--select * from tblClosingStock cs
-- [rptrm_pm_stck_summary] '2011-1-1','2012-12-1'
END