title: SQL query find for how many days are there blog entries
body: <p>I'm trying to come up with a way to query my blog database to find out which days within a certain range have posts.</p>
  
  <p>Eg. If my dates are 1/1/2012 - 1/30/2012, how many of those 30 days contain at least one blog post?</p>
  
  <p>My dates are stored as: 0000-00-00 00:00:00</p>