title: SQL Group By error ORA-00979
body: <p>I'm trying to give this query:</p>
  
  <pre><code>select s_name, course from Student group by course;
  </code></pre>
  
  <p>But I get an error (ORA-00979 Not a GROUP BY EXPRESSION).</p>
  
  <p>I want to list the names of all the students that are in the same course.
  Is there another method of doing this? If not, what is the proper way to implement this query? I would appreciate if someone could give me the exact code required.</p>