I have an INVOICE table with INV_NO as primary key with index.
Table also has ITEM_NO for the line items.
I normally select from table/view as this
SELECT col1,col2,... from INVOICE where INV_NO=p_inv_no
ORDER BY item_no.
Would it help to have the index replace by (INV_NO, ITEM_NO) or not since it is only used for sorting result set and not in the WHERE clause