title: Concat all column values in sql
body: <p>How to concat all column values from differenct rows returned from a sql query into one value? This is an example:</p>
  
  <p>a query returns:</p>
  
  <pre>
  FOO
  ------
  RES1
  
  RES2
  
  RES3
  </pre>
  
  <p>now I want to have a result like the following one:</p>
  
  <pre>
  FOOCONCAT
  -----
  RES1RES2RES3
  </pre>
  
  <p>Are there any ways to do this in sql?</p>