title: How can I "subtract" one table from another?
body: <p>I have a master table <code>A</code>, with ~9 million rows. Another table <code>B</code> (same structure) has ~28K rows from table <code>A</code>. What would be the best way to remove all contents of <code>B</code> from table <code>A</code>?</p>
  
  <p>The combination of all columns (~10) are unique. Nothing more in the form a of a unique key.</p>