how to display only 20 items of the result in oracle sql?

Question

Is it possible to display only 20 items of the whole result? I know of a query "rownum>=20" but that only makes the sql check only the first 20 rows in the table. But i want the sql to check my whole table and display only the highest 20 entries.

To be clear, I have a table with job description like Title, description, agency, salary_min, salary max. I want to display the 20 highest paying jobs.

Answer 1

The "highest" 20 entries suggests a sort. You would do something like this:

select t.*
from (select t.*
      from table t
      order by highestcol desc
     ) t
where rownum <= 20;

If you are using Oracle 12g or more recent, you can use the fetch first clause instead:

select t.*
from table t
order by highestcol desc
fetch first 20 rows only;