title: Is there any function in oracle similar to group_concat in mysql?
body: <p>My inputs are in this way.</p>
  
  <pre><code>col1   col2
  1      a
  1      b
  2      c
  2      d
  2      e
  </code></pre>
  
  <p>O/p: Should Be like</p>
  
  <pre><code>col1    col2
  1       a,b
  2       c,d,e
  </code></pre>
  
  <p>I want a query that can be fired at DB level. I've tried various ways, but wasn't able to make this out...</p>