title: Change column type from varchar to timestamp
body: <p>I have a table that is defined like this:</p>
  
  <pre><code>CREATE TABLE session_requests
  (
    id character varying(255) NOT NULL,
    authorization_enc character varying(255),
    auto_close integer,
    date_created character varying(255) DEFAULT '1970-01-01 01:00:00'::character varying,,
  ....
  )
  </code></pre>
  
  <p>I'm trying to do </p>
  
  <pre><code>alter table session_requests alter column date_created type timestamp using date_created::timestamp;
  </code></pre>
  
  <p>the error that I'm getting is</p>
  
  <pre><code>ERROR:  default for column "date_created" cannot be cast automatically to type timestamp
  </code></pre>
  
  <p>Anyone has any suggestions?</p>