This can be done in several ways in Oracle.
Oracle 12c onwards - Just add "FETCH FIRST 25 ROWS ONLY" at the end of your query.
Example: Select * From employee order by salary desc FETCH FIRST 25 ROWS ONLY;
Other ways of doing this:
using ROWNUM --> Select * From employee where rownum <= 25 order by salary desc;
The same can also be done using other oracle analytic functions like RANK, DENSE_RANK, ROW_NUMBER, PERCENT_RANK, NTILE