title: Oracle Add Date Column to Existing Table (default to sysdate new rows only)
body: <p>Is there a way to add column DATE_CREATED such as only new rows will pickup the default sysdate?  When I ran the ALTER below, all priors rows got the DATE_CREATED set to the run-time of the ALTER script; I would prefer them to remain null. </p>
  
  <pre><code>alter table abc.mytable
    add 
      (DATE_CREATED        date   default sysdate null
      ); 
  </code></pre>