Can this sql be tuned?

[slimdave]

You'd probably only be interested in indexing the "N" values-- including the "Y"'s in the index would be a waste of time.

You can do this with a function-based index, by ..

create index
   my_index
on dt_company_contact_person 
   (Decode(dm_ind,'N','N',Null));

You would then access the indexed "N" values by querying ..

Where
   Decode(dm_ind,'N','N',Null) = 'N'