Oracle Text Boolean search

hi, can someone provide some insights how I can rewrite my boolean search query more efficiently?

I would like to do a search for something like "(a AND b) or (c AND d) or (e AND f)..."

The query I have formulated does not scale well when I have multiple AND's and OR's.

 select * from (

     (   select id, name from testtable tab1
         where tab1.type='HEADING'
         and contains (value, 'a')>1
         AND EXISTS
         (select id, name from testtable tab2
          where tab1.id=tab2.id
           and tab2.type='BODY'
           and  contains (value, 'b')>1
         )


     )

     UNION
     (   select id, name from testtable tab1
         where tab1.type='BODY'
         and contains (value, 'c')>1
         AND EXISTS
         (select id, name from testtable tab2
          where tab1.id=tab2.id
           and tab2.type='SUBHEADING'
           and  contains (value, 'd')>1
         )


     )

      UNION
       ...
       ...
        and so on....

appreciate any help.

thanks.

geraldine

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