title: Ambiguous error when using INNER JOIN
body: <p>I am trying to select deptno, dname from the depts table and join it with the emp table to select empno and ename.  Then I want group them by department name by sort by deptno ascending.<br>
    When joining these two tables I keep getting 'deptno' is ambiguous. But that is the commonality to join the tables. Any helpful advice where my error may be with </p>
  
  <pre><code>SELECT deptno, dname, empno, ename
  FROM dept INNER JOIN emp
  ON dept.deptno = emp.deptno
  GROUP BY dname
  ORDER BY deptno ASC; 
  </code></pre>
  
  <p>Thank you for any helpful advice.</p>