title: Concatenate multiple rows in an array with SQL on PostgreSQL
body: <p>I have a table constructed like this :</p>
  <pre><code>oid | identifier | value
  1   | 10         | 101
  2   | 10         | 102
  3   | 20         | 201
  4   | 20         | 202
  5   | 20         | 203
  </code></pre>
  <p>I'd like to query this table to get a result like this :</p>
  <pre><code>identifier | values[]
  10         | {101, 102}
  20         | {201, 202, 203}
  </code></pre>
  <p>I can't figure a way to do that.<br />
  Is that possible? How?</p>