title: How to parse json value of text column in postgres
body: <p>I have a column of text type be contain json value.<br/></p>
  
  <pre><code>{"summary":"this is a example","url":"stackoverflow.com"}
  </code></pre>
  
  <p>How can I extract '<strong>url</strong>' json field of column in postgres with query?</p>
  
  <p>I used of following query:</p>
  
  <pre><code> SELECT jvalue-&gt;&gt;'url' From table;
  </code></pre>
  
  <p>With my query, I get following error.<br/></p>
  
  <blockquote>
    <p>SQL Error [42883]: ERROR: operator does not exist: text ->> unknown
    Hint: No operator matches the given name and argument type(s). You
    might need to add explicit type casts.
    org.postgresql.util.PSQLException: ERROR: operator does not exist:
    text ->> unknown Hint: No operator matches the given name and argument
    type(s). You might need to add explicit type casts.</p>
  </blockquote>