title: select salgrade when sal is given where they both are from different tables and no common column exists between them
body: <p>this is my salgrade table</p>
  
  <pre><code>grade losal   hisal
  1   700.00  1200.00
  2   1201.00 1400.00
  3   1401.00 2000.00
  4   2001.00 3000.00
  5   3001.00 9999.00
  </code></pre>
  
  <p>and this is my emp table</p>
  
  <pre><code>sal     empno   ename
  800.00  7369    SMITH
  1600.00 7499    ALLEN
  1250.00 7521    WARD
  2975.00 7566    JONES
  1250.00 7654    MARTIN
  2850.00 7698    BLAKE
  2450.00 7782    CLARK
  3000.00 7788    SCOTT
  5000.00 7839    KING
  1500.00 7844    TURNER
  1100.00 7876    ADAMS
  950.00  7900    JAMES
  3000.00 7902    FORD
  1300.00 7934    MILLER
  </code></pre>
  
  <p>By using these tables I need to select sal when two grades are given</p>