title: Subtract last year's ending quarter value from current quarter value
body: <p>I know </p>
  
  <pre><code>(DateAdd("s",-1,
  DateAdd("q",DateDiff("q","1/1/1900",
  DateAdd("yyyy",-1,Date())),"1/1/1900")),
  "Short Date") 
  </code></pre>
  
  <p>returns the last day of a quarter 1 year ago.</p>
  
  <p>All of the NAV_Dates are the last day of each quarter, and have a value associated with them which makes the row unique. (Closing value titled as NetAssetValue)</p>
  
  <p>How can I use that (or something similar), to get the value associated with the ending year quarterly date, and subtract it from the value of the current quarter's ending value. Note: I do not have to use this, it's just the only SQL I know that will return a value to somewhat close to what I need.</p>
  
  <p>The table's values would be set up similar to this:</p>
  
  <pre><code>+----------+--------------+
  |NAV_Date  |NetAssetValue |
  +----------+--------------+
  |12/31/2012|        $4,000|
  +----------+--------------+
  |03/31/2013|        $5,000|
  +----------+--------------+
  </code></pre>
  
  <p>The Year to Date would then be (5,000/4,000) - 1 and saved as a percent. Another example would be:</p>
  
  <pre><code>+----------+--------------+
  |NAV_Date  |NetAssetValue |
  +----------+--------------+
  |12/31/2012|        $4,000|
  +----------+--------------+
  |06/30/2013|        $4,025|
  +----------+--------------+
  </code></pre>
  
  <p>Year to Date calculation: (4,025/4,000) - 1 and saved as a percent.</p>
  
  <p>I know it involves a nested subquery (or possibly more than one) and that we'd essentially have to capture the current quarter's end, use that value, and capture the prior year's quarter end and use that value also. Just not quite sure how to do it.</p>