Does anyone know whi am not getting correct result here
I have two tables
bkmed varchar2(10) (CD, DVD)
Master table is books. The book that selected to convert from CD to DVD are added to CONV
with bkmed="CD". After that a new ROW is added to BOOKS with "DVD" media.
I want to know the books in CONV that do not have a DVD record in BOOKS
sql> select count(*) from conv;
sql> select bkno from conv where bkno not in (select bkno from books where bkmed='DVD')
sql> select bkno from conv where bkno in (select bkno from books where bkmed='DVD')
so why the 3510 books which i know are not in books showing up.
Every book in CONV get added from BOOKS table.