A difficult query

Hi, NG,

I can't find a fine solution for my problem:

From two tables I need similar colums. From table A I need all rows except from those, which are marked in table B. From table B I need all rows except from those, which are not in table A. Here is an example:

Rows of table A (id):
 1
 2
 3
 4

Rows of table B (id, mark):

 2,
 3,
 4,X   <-- not wanted, because it's marked
 5,    <-- not wanted, because it's not in table A

(select * from A where A.id = B.id)

But this seems to me a bit complicated. In reality both main selects are very complex, so that I get a huge resulting SQL-statement which is probably not quite performant (In fact I generate it by java).

Does somebody know a better solution?

Thx in advance for each little hint.

Conny Received on Sun Sep 08 2002 - 01:43:10 CEST