title: Remove all duplicates from Redshift database
body: <p>I have a very large Redshift database. The records do not have unique keys or ids. I'd like to remove all of the duplicates with the most efficient query possible. </p>
  
  <p>Other stackoverflow questions about typical sql databases suggested copying the table and skipping the duplicates during that process, but that seems suboptimal for a giant redshift database. </p>
  
  <p>Any better solutions out there?</p>