title: GROUP BY but get all values from other column
body: <p>I''ll explain what I need to do on example. First of all, we have a simple table like this one, named <em>table</em>:</p>
  
  <pre><code>id | name
  ===+=====
  1  | foo
  1  | bar
  1  | foobar
  2  | foo
  2  | bar
  2  | foobar
  </code></pre>
  
  <p>Now the query:</p>
  
  <pre><code>SELECT t.* FROM table t GROUP BY t.id
  </code></pre>
  
  <p>Will get us result similar to this one:</p>
  
  <pre><code>id | name
  ===+=====
  1  | foo
  2  | foo
  </code></pre>
  
  <p>But is it possible, to collect all values of <em>name</em> to have result like this?</p>
  
  <pre><code>id | name
  ===+=================
  1  | foo, bar, foobar
  2  | foo, bar, foobar
  </code></pre>