title: Error for Querying JSON in Postgres: function json_extract_path_text(text, text) does not exist
body: <p>I'm trying to set up a view based on a query to a <em>text</em> column that contains JSON in the latest version (9.3.4) of Postgres, but I get an error that I have not been able to find any discussion about.</p>
  
  <p>Let's assume the table is called <em>table1</em> and the particular column, <em>json_data</em>, has something like</p>
  
  <pre><code>{"item1": "value1", "item2": "value2", "item3": 3, "item4": 4, "item5": 5}
  </code></pre>
  
  <p>Here is my query:</p>
  
  <pre><code>SELECT 
  json_extract_path_text((table1.json_data)::text, 
  ('item1'::character varying)::text) AS item1
  FROM
  table1
  </code></pre>
  
  <p>The error I get is</p>
  
  <pre><code>ERROR:  function json_extract_path_text(text, text) does not exist
  LINE 2: json_extract_path_text((table1.json_data)...
  HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
  </code></pre>
  
  <p>I'm lost on how to fix this. (Also, I have a similar view that works completely fine using the same syntax on a similar <em>text</em> column in the particular table.)</p>