title: Is it possible to complete this request without join and union?
body: <p>Assume there is a table a and its content is:</p>
  
  <pre><code>col1   col2
  a      1
  b      2
  c      2
  d      1
  e      1
  </code></pre>
  
  <p>Now, is it possible to write one <code>select..from..</code> <strong>without</strong> <code>join</code> or <code>union</code> to get amount of 1 in col2 / amount of all elements in col1 (in this case, 3/5)?</p>
  
  <p>I'm using ORACLE. Any help is appreciated.</p>
  
  <hr>
  
  <p>Sorry I did not put a proper example at the beginning..the elements in col1 are not same.. </p>