title: subselect vs outer join
body: <p>Consider the following 2 queries:</p>
  
  <pre><code>select tblA.a,tblA.b,tblA.c,tblA.d
  from tblA
  where tblA.a not in (select tblB.a from tblB)
  
  select tblA.a,tblA.b,tblA.c,tblA.d
  from tblA left outer join tblB
  on tblA.a = tblB.a where tblB.a is null
  </code></pre>
  
  <p>Which will perform better?  My assumption is that in general the join will be better except in cases where the subselect returns a very small result set.</p>