Noget forenklet til at begynde med:
SELECT A.Num1
,A.Num2
,NVL(
(SELECT DISTINCT
FIRST_VALUE(B.Status)
OVER (ORDER BY B.Date DESC)
FROM B
WHERE B.Num1 = A.Num1
AND B.Num2 = A.Num2
AND B.Date <= A.Date
),'New') AS Status
,A.Date
FROM A;
Der er sandsynligvis en bedre metode, der kan virke hurtigere.