title: What difference between NULL and NULL::character varying in PostgreSQL
body: <p>Is there a difference between default values of column in PostgreSQL? Whether this is important?</p>
  
  <pre><code>state character varying(255) DEFAULT NULL
  </code></pre>
  
  <p>and</p>
  
  <pre><code>state character varying(255) DEFAULT NULL::character varying
  </code></pre>