title: How to create a Datum for database NULL in PostgreSQL a server side C function?
body: <p>I was just wondering how to create a Datum for the database <code>NULL</code> value in PostgreSQL?</p>
  
  <p>I known there is <code>PG_RETURN_NULL()</code> for <em>returning</em> a database NULL in a <code>LANGUAGE C</code> function. But I just want to create a Datum for <code>NULL</code>, e.g. to be stored in an array (or record). Should I just use <code>(Datum) 0</code>?</p>
  
  <p>(This is with PostgreSQL 12)</p>