title: How do I update a JSON column with a NULL value?
body: <p>Hi Im trying to add / update data in my json column - where the value inside is NULL
  not having much luck - here is my query that errors</p>
  
  <pre><code>update departments 
  set (data-&gt;&gt;'formal_name') = departments.name 
  where (data-&gt;&gt;'formal_name') is null
  </code></pre>
  
  <p>thanks for any suggestions</p>