Select Negation

Question

Hi!
I've got this Select Statement with a count of 350:
SELECT Count(*) FROM table_a a
WHERE a.f1 = 'AA'
AND a.f2 = '2005'
AND a.f3 IN ('PBW1', 'PBW2')
A Select count(*) from table_a has 1141637 counts.
Now I have to negate this select to get all Datasets I don't want.
SELECT Count(*) FROM table_a a
WHERE a.f1 <> 'AA'
OR (a.f2 = 'AA' AND a.f2 <> '200508')
OR (a.f2 = 'AA' AND a.f2 = '200508' AND a.f3 NOT IN ('PBW1', 'PBW2'))
But this count gives me 1138023 Datasets. This is not correct. There must be more (see 1141637 without where statement). With debugging I found out, that everything works fine up to the second AND Statement.
Negating AND a.f3 IN ('PBW1', 'PBW2')
to OR (a.f2 = 'AA' AND a.f2 = '200508' AND a.f3 NOT IN ('PBW1', 'PBW2'))
brings the error or mistake or what ever. Using where not(...) or other options also doesn't work.
Where is my Mistake? What do do? Couldn't I negate an IN statement?
How can I solve this Problem???
Greets
Sascha

Answer 1

Got any NULL values in one of those fields? If yes, those Records would fail both the initial and the NOT where clause.
See this example:
WITH table_a AS (SELECT 'AA' f1, '2005' f2, 'PBW1' f3
                   FROM dual
                  UNION
                 SELECT 'AA' f1, '2005' f2, 'PBW2' f3
                   FROM dual
                  UNION
                 SELECT null f1, '2005' f2, 'PBW2' f3
                   FROM dual
SELECT COUNT (*)
  FROM table_a a
WHERE NOT (
       a.f1 = 'AA'
   AND a.f2 = '2005'
   AND a.f3 IN ('PBW1', 'PBW2')
   );Count returns 0 records.
C.
Message was edited by:
cd