title: Concatenate values from multiple columns in Oracle
body: <p>I'm working with an oracle database and what I basically need to concatenate in one column, values from multiple columns for every row.</p>
  
  <p>Something like this:</p>
  
  <pre><code>col1    col2    col3    col4    col5
  ____________________________________
   1       A       B       C       D
   2       A       B       C
   3       C       A
   4       D       A       C
  
  col1    col2
  ____________
   1      A,B,C,D
   2      A,B,C
   3      C,A
   4      D,A,C
  </code></pre>