Listing A

SELECT
   sales_rep_id, customer_id, order_total,
   ratio_to_report(order_total) OVER () pct_total
FROM
   orders
WHERE
   sales_rep_id = 163
ORDER BY
   sales_rep_id, customer_id, order_id
/

SQL> @ratioreport_a

SALES_REP_ID CUSTOMER_ID ORDER_TOTAL  PCT_TOTAL                                 
------------ ----------- ----------- ----------                                 
         163         102      5610.6 .043747539                                 
         163         102       10523 .082051002                                 
         163         103          78  .00060819                                 
         163         103       13550 .105653433                                 
         163         105      1926.6 .015022281                                 
         163         106      5546.6 .043248512                                 
         163         117      3878.4 .030241054                                 
         163         147      1500.8  .01170219                                 
         163         149        9055 .070604564                                 
         163         156       68501  .53412294                                 
         163         157      7110.3 .055441152                                 
         163         160       969.2 .007557144                                 

12 rows selected.

SQL>