title: Check if entry in table A exists in table B
body: <p>I have a definition table that I know is not being maintained very well, let's call this <code>table A</code>. I have another table (call it <code>table B</code>) that is much smaller and ideally should be a <code>subset of table A</code> but I know that <code>table A</code> is somewhat stale and does not contain new entries that are in <code>Table B</code>.</p>
  <p>Note, that tables A and B have different columns.</p>
  <pre><code>Table A:
  ID, Name, blah, blah, blah, blah
  
  Table B:
  ID, Name
  </code></pre>
  <p>I want all rows in Table B such that the ID in Table B does NOT exist in Table A. This does not just match rows in Table A; I want only rows in Table B where the ID does NOT exist at all in Table A.</p>