title: use of group by clause in oracle apex
body: <p>First of all,I am new to Oracle that's why my question may be funny for experienced developers. Sorry for that in advance.</p>
  
  <p><strong>Ques.</strong> I have a table Test with 3 cols (ID, Name, Group_name)</p>
  
  <p><strong>Table</strong></p>
  
  <pre><code>ID | Name | Group_name
  1  | name1 | group 1 
  2  | name2 | group 1  
  3  | name3 | group  1 
  4  | name4 | group 2
  5  | name5 | group 2
  </code></pre>
  
  <p>I want to create a select list in oracle apex .</p>
  
  <p>-Select-</p>
  
  <pre class="lang-none prettyprint-override"><code>(Group 1)
  Name 1
  Name 2
  Name 3
  (Group 2)
  Name 4
  Name 5
  </code></pre>
  
  <p>in which <strong>Group1</strong> &amp; <strong>Group2</strong> are only for display and are not selectable.</p>
  
  <p>I tried: </p>
  
  <pre><code>SELECT NAME, ID
  FROM TEST
  GROUP BY GROUP_NAME
  </code></pre>
  
  <p>gives error:</p>
  
  <blockquote>
    <p>not a group by expression</p>
  </blockquote>