Working with Returned Null Values and Dates

Ok; I have modified the file that has been delivered to me from the supplying vendor and it worked the way it should. However; I am faced with yet another small issue. When I try and select from my under lying table (New table with no data) to compare dates ; I of-course will receive a null value in my select statement. In the code snippet below, this works perfectly well if there is data in my base table APP_REGISTRAR.T_VIRTUAL_ORIENT; but if there is no data in this table because it is a new table, how can I compensate for a returned NULL value of a date datatype so that it will still bring across the initial data from my External table? I am currently running on Oracle 11g.

SELECT NETID, TO_DATE(COMP_DATE,  'YYYY-MM-DD HH24:MI:SS') "COMP_DATE"
FROM APP_REGISTRAR.T_EXTERNAL_VIRTUAL_ORIENT
WHERE TO_DATE(COMP_DATE, 'YYYY-MM-DD HH24:MI:SS') > (SELECT MAX(b.COMP_DATE) FROM APP_REGISTRAR.T_VIRTUAL_ORIENT b);