Oracle 10g, SQL Query to count missing rows

Experts,
I need a query to count the number of rows missing between two tables. Pretty simple, this works fine;

select COUNT(ORD_LINE_NUM)
from E_ORD_D5 
where comp_code = 'A1' 
and ord_num = 916393
and ORD_LINE_NUM not in (
select ord_line_num from E_ord_d5d2
where comp_code = 'A1'
and ord_num = 916393)

Select allOpen in new window

Heres where I am stuck..  the query has 2 parameter fields COMP_CODE and ORD_NUM. Each is currently used twice. My application will only pass the two values one time.  How can I add joins to this query so that the parameters are only set once?