title: Oracle Regexp_replace multiple occurrence
body: <p>Hi I want to append a letter C to a string if it starts with a number .
  Also if it has any punctuation then replace with underscore _
  Eg : 5-2-2-1  ==> C5_2_2_1</p>
  
  <p>I tried ,but I am not able to replace the multiple occurrence of the punctuation. I am missing some simple thing, I cant get it.</p>
  
  <pre><code>SELECT  REGEXP_REPLACE('9-1-1','^(\d)(-),'C\1_' ) FROM DUAL;
  </code></pre>