title: Postgres sorting is not working on special characters using collate
body: <p>If I execute the postgresql script using collate, I am getting the result sorted only with '.' and it dint consider '__'. I want the special characters '.' and '_' to be sorted first followed by alphabets.</p>
  <pre><code>PostgreSQL:
  SELECT * FROM test_spl_char ORDER BY CHR_NM COLLATE &quot;C&quot;;
  Output:
  -----------
  .GEMS
  BISCUIT
  CANDY
  DONUT
  YUM
  _SHAKE
  
  show lc_collate;
  Output:
  -----------
  en_US.UTF-8
  </code></pre>
  <p>Kindly help me in getting the result sorted with special chars first.</p>