title: ERROR: function unnest(integer[]) does not exist in postgresql
body: <pre><code>SELECT UNNEST(ARRAY[1,2,3,4])
  </code></pre>
  
  <p>While executing the above query I got the error like this:</p>
  
  <pre><code>ERROR: function unnest(integer[]) does not exist in postgresql.
  </code></pre>
  
  <p>I am using PostgreSQL 8.3 and I have installed the <code>_int.sql</code> package in my db for integer array operation.</p>
  
  <p>How to resolve this error?</p>