rownum notworking with subquery on oracle

Question

I have a long query with multiple joins,

Select * 
  from (Select firstName, lastname, designation 
          from NameTable nameT 
          left outer join ProfileTable profileT on nameT.id = profileT.id
          where firstName like ("S%") order by firstName ASC
       ) 
  where rownum < 25

The above query works fine, If i change the name search to "sa" then query executing get hanging.

If i change the rownum to 21 "sa" query also gets fast.

Whether we need to add any index to table, or any idea for this question.

Thanks in Advance!!!

Answer 1

why you want to go for subquery here,I think it will help you

  Select firstName, lastname, designation 
   from NameTable nameT left outer join ProfileTable profileT 
   on nameT.column=profileT.column    
  where firstName like ("S%") and rownum < 25