title: Using Excel's SUMIFS function with a date criteria
body: <p>I have a data:</p>
  
  <pre><code>A         B      C
  13524   2012-07  2
  13524   2012-08  9
  13524   2012-09  5
  13524   2012-10  2
  13524   2012-11  7
  </code></pre>
  
  <p>Now i would like to sum the values in <code>column C</code>, if date is greater than value specified in a cell:</p>
  
  <pre><code>  D         E       F
  13524    2012-09
  </code></pre>
  
  <p>Above, in cell under <code>column F</code>, I write:</p>
  
  <pre><code>=SUMIFS($C:$C,$A:$A,D1,$B:$B,"&gt;="&amp;E1)
  </code></pre>
  
  <p>which will give me the sum of values that have greater or equal to date than 2012-09, so the result should be <code>5+2+7 = 14</code>, but it returns 0. What is wrong above?</p>