Select * from emp 

SELECT   Row_number()
           OVER(ORDER BY d_style.d_style_no) AS ser#,
         description,
         order_quantity,
         dis.dqty,
         Nvl(order_quantity,0) - Nvl(dis.dqty,0) AS "Bal to Supply",
         ret.rqty
FROM     d_style,
         d_order,
         (SELECT   d_stitch_style_no           stisty,
                   Sum(Nvl(stitch_quantity,0)) sqty
          FROM     d_stitch
          WHERE    d_stitch_date BETWEEN Nvl(:Date_from,d_stitch_date) AND Nvl(:Date_to,d_stitch_date)
          GROUP BY d_stitch_style_no) sti,
         (SELECT   d_dispatch_style_no           dissty,
                   Sum(Nvl(dispatch_quantity,0)) dqty
          FROM     d_dispatch
          WHERE    d_dispatch_date BETWEEN Nvl(:Date_from,d_dispatch_date) AND Nvl(:Date_to,d_dispatch_date)
          GROUP BY d_dispatch_style_no) dis,
         (SELECT   d_return_style_no           retsty,
                   Sum(Nvl(return_quantity,0)) rqty
          FROM     d_return
          WHERE    d_return_date BETWEEN Nvl(:date_from,d_return_date) AND Nvl(:date_to,d_return_date)
          GROUP BY d_return_style_no) ret
WHERE    sti.stisty (+)  = d_style.d_style_no
         AND dis.dissty (+)  = d_style.d_style_no
         AND ret.retsty (+)  = d_style.d_style_no
         AND d_style_no BETWEEN Nvl(:Style_from,d_style_no) AND Nvl(:Style_to,d_style_no)
         AND d_catagory_name = Nvl(:Catagory,d_catagory_name)
GROUP BY d_style_no,
         sti.sqty,
         dis.dqty,
         ret.rqty,
         order_quantity,
         description 

SELECT COUNT(*) 
FROM <your_query_here> 
WHERE item_value >= 0   /   or item_value < 0

WHERE item_value >= 0   /   or item_value < 0

Nvl(order_quantity,0) - Nvl(dis.dqty,0) AS "Bal to Supply",

SUM (CASE WHEN "Bal to Supply" > 0 THEN 1 ELSE 0 END) positive_balances,
SUM (CASE WHEN "Bal to Supply" < 0 THEN 1 ELSE 0 END) negative_balances,