Why repeat the same conditions twice? Try
SELECT i.* from table1 i
WHERE (i.field1 = 'FA' and field2 IN('AAA','BBB') AND i.field3 = 0)
AND NOT EXISTS (SELECT * from table3 a WHERE a.table2id = i.table2id AND a.field4 = i.field4))
AND (EXISTS (SELECT * from table2 s WHERE s.table2id = i.table2id AND s.fielda <> 'X' AND s.fieldb <> 'I')
OR NOT EXISTS (SELECT * from table2 s WHERE s.table2id = i.table2id))>I think this works:
>
>SELECT i.* from table1 i
> WHERE (((i.field1 = 'FA' and (field2 = 'AAA' or field2 = 'BBB') AND i.field3 = 0)
> AND EXISTS (select * from table2 s where s.table2id = i.table2id AND s.fielda <> 'X'
> AND s.fieldb <> 'I')
> AND NOT EXISTS (SELECT * from table3 a where a.table2id = i.table2id
> AND a.field4 = i.field4))
> OR
> ((i.field1 = 'FA' and (field2 = 'AAA' or field2 = 'BBB') AND i.field3 = 0)
> AND NOT EXISTS (select * from table2 s where s.table2id = i.table2id)
> AND NOT EXISTS (SELECT * from table3 a where a.table2id = i.table2id
> AND a.field4 = i.field4)))
>
--sb--
