title: Get json value in pl/pgsql
body: <p>I have json string like <code>'{"ww":11}'</code></p>
  
  <p>How can i get value 11 in pl/pgsql ?</p>
  
  <p>I try:</p>
  
  <pre><code>json_var := '{"ww":11}'::json
  
  json_var-&gt;ww;
  json_var-&gt;"ww";
  json_var.ww;
  </code></pre>
  
  <p>All of this failed.</p>
  
  <p>Please help!
  Dmitry</p>