title: Custom Magento Report for Taxable/Non-Taxable sales
body: <p>Let me preface by saying I'm new to Magento as well as Data Collections in general (only recently begun working with OOP/frameworks).</p>
  
  <p>I've followed the excellent tutorial <a href="http://wrightcreativelabs.com/create-a-custom-magento-report-product-skus-in-new-orders/" rel="nofollow">here</a> and I'm familiar with Alan Storm's overviews on the subject.  My aim is to create a custom Magento report which, given a start/end date, will return the following totals:</p>
  
  <ul>
  <li>Taxable Net (SUM subtotal for orders with tax)</li>
  <li>Non-Taxable Net (SUM subtotal for orders without tax)</li>
  <li>*Total Gross Sales (Grand total)</li>
  <li>*Total Net Sales (Grand subtotal)</li>
  <li>*Total Shipping</li>
  <li>*Total Tax</li>
  </ul>
  
  <p>*For these figures, I realize they are available in existing separate reports or can be manually calculated from them, however the purpose of this report is to give our store owner a single page to visit and file to export to send to his accountant for tax purposes.</p>
  
  <p>I have the basic report structure already in place in Adminhtml including the date range, and I'm confident I can include additional filters if needed for order status/etc. Now I just need to pull the correct Data collection and figure out how to retrieve the relevant data.</p>
  
  <p>My trouble is I can't make heads or tails of how the orders data is stored, what Joins are necessary (if any), how to manipulate the data once I have it, or how they interface with the Grid I've set up.  The existing tutorials on the subject that I've found are all specifically dealing with product reports, as opposed to the aggregate sales data I need.</p>
  
  <p>Many thanks in advance if anyone can point me in the right direction to a resource that can help me understand how to work with Magento sales data, or offer any other insight.</p>