title: Using PIVOT to Flip Data from Wide to Tall
body: <p>I have a table that is rather wide that I would like to convert to tall.  The data currently resides like this:</p>
  
  <pre><code>VEND   YEAR   I1_DOLS   I1_QTY   I2_DOLS   I2_QTY   I3_DOLS   I3_QTY ...
  1234   2011   101587    508      203345    334      105938    257
  1234   2012   257843    587      235883    247      178475    456
  1011   2010   584737    432      587274    356      175737    563
  1011   2011   517774    356      483858    456      481785    354
  </code></pre>
  
  <p>I would like to convert this to a table that looks like this:</p>
  
  <pre><code>VEND   YEAR   MONTH   DOLS     QTY
  1234   2011   1       101587   508
  1234   2011   2       203345   334
  1234   2011   3       105938   257
  1234   2012   1       257843   587
  1234   2012   2       235883   247
  .
  .
  .
  </code></pre>
  
  <p>I assume that a PIVOT is what I need, but I can't seem to figure this out.</p>