title: Replace/delete field using sqlalchemy
body: <p>Using postgres in python,</p>
  
  <ol>
  <li><p>How do I replace all fields from the same column that match a specified value? For example, let's say I want to replace any fields that match "green" with "red" in the "Color" column.</p></li>
  <li><p>How to delete all fields from the same column  that match a specified value? For example, I'm trying to deleted all fields that match "green" in the Color column.</p></li>
  </ol>