title: postgresql Jsonb ? is not working
body: <p>I am using postgres 9.4 and i have a table test_table where the definition is:</p>
  
  <pre><code>id (primary key) integer, meta_data json, version integer
  </code></pre>
  
  <p>The Table data is as follows:</p>
  
  <pre><code>1;"{"id":99,"file_name":"test.pdf"}";0
  2;"{"id":101,"nest1":{"nest_name_1":"oxford"},"file_name":"test2.pdf"}";0
  </code></pre>
  
  <p>I want to find all the primary keys that contain the keyword oxford. so the expected result is 2. </p>
  
  <p>I am still trying to find a solution and i was trying something like:</p>
  
  <pre><code>select * from test_table where meta_data ? 'oxford'
  </code></pre>
  
  <p>gives me:</p>
  
  <blockquote>
    <p>Error: operator does not exist: json ? unknown</p>
  </blockquote>
  
  <p>thats making me confused. surely postgresql 9.4 has ? operator right? what is going on?</p>
  
  <p>can someone help me please.</p>
  
  <p>Thanks in advance</p>