title: How to determine if NULL is contained in an array in Postgres?
body: <p>How do I determine if NULL is contained in an array in Postgres? Currently using Postgres 9.3.3.</p>
  
  <p>If I test with the following select it returns <code>contains_null = false</code>.</p>
  
  <pre>
  <code>select ARRAY[NULL,1,2,3,4,NULL]::int[] @> ARRAY[NULL]::int[] AS contains_null
  select ARRAY[NULL,1,2,3,4,NULL]::int[] @> NULL AS contains_null
  </code></pre>
  
  <p>I've also tried with:</p>
  
  <ol>
  <li>@> (contains)</li>
  <li>&lt;@ (is contained by)</li>
  <li>&amp;&amp; (overlap)</li>
  </ol>