title: Jooq ArrayAgg#isNull not working as expected
body: <p>I have a project which uses jooq + postgres with multiple tables and relations between them.</p>
  <p>while I was creating a <code>select</code> query with jooq I had to use <code>arrayAgg</code> for my specific scenario.</p>
  <p><code>dslContext.select(arrayAgg(tableName.INTEGER_LETS_SAY).as(&quot;static_name&quot;)</code></p>
  <p>the specific column <code>INTEGER_LETS_SAY</code> is nullable.
  when the results passed in <code>arrayAgg</code> are all <code>null</code> then the response of the postgres is '{null}' ( tested with <code>getQuery().getSql()</code> ) but the <code>where</code> statement cannot return <code>true</code> for all the methods I tried.</p>
  <p>for example :</p>
  <ul>
  <li><code>field(&quot;static_name&quot;, Long[].class).isNull()</code></li>
  <li><code>field(&quot;static_name&quot;, Long[].class).equal(new Long[] {null})</code></li>
  <li><code>field(&quot;static_name&quot;, Long[].class).equal(DSL.castNull(Long[].class)</code></li>
  <li><code>field(&quot;static_name&quot;, Long[].class).cast(String.class).eq(DSL.value(&quot;{null}&quot;)))</code></li>
  <li><code>field(&quot;static_name&quot;, Long[].class).cast(String.class).eq(DSL.value(&quot;'{null}'&quot;)))</code></li>
  </ul>
  <p>any clue what am I doing wrong?</p>
  <p>Note : I did try the query with plain sql and <code>static_name = '{null}'</code> worked</p>