title: List all of the donors who have donated a total amount greater than something
body: <p>This is table structure</p>
  
  <p>Donor (<strong>donorID</strong>, name)<p>
  Donation (<strong>ID</strong>, donorID, amount)</p>
  
  <p>Here is my query :<p></p>
  
  <pre><code>SELECT donor.name, SUM(donation.amount) "Total"
  FROM donor, donation
  WHERE donor.donorID = donation.donorID
  AND SUM(donation.amount) &gt; 1000;
  GROUP BY donor.name
  ORDER BY SUM(donation.amount) DESC;
  </code></pre>
  
  <p>Here is the error: </p>
  
  <blockquote>
    <p>ORA-00934: group function is not allowed here
    00934. 00000 -  "group function is not allowed here"</p>
  </blockquote>
  
  <p>There is not error when i remove the sum(donation) &lt; 1000
  How do i integrate it without error? Please help.</p>