Solved it. This sql goes through the whole WHERE statement. I added a CASE (see below)
CASE WHEN LENGTH(datedc) = 10 THEN
to_date( to_char(substr(datedc,7,4)) + '-' + to_char(substr(datedc,4,2)) + '-' + to_char(substr(datedc,1,2)))
END > add_months(sysdate - dayofmonth(sysdate) ,-2)
I...