You can extract a subset of rows from a table using comparison operators. There are 6 basic comparisons.

=	equal to
!=	not equal to
>	greater than
>=	greater than or equal to
<	less than
<=	less than or equal to

You use these in a WHERE clause. For instance, to list all the employees who have a surname EQUAL TO 'Wright':

  SELECT empno, surname, telno
  FROM employee
  WHERE surname = 'Wright'

Try listing the empno and salary from jobhistory where the salary is greater than or equal to 20000.