title: lookup previous date for same ID
body: <p>I want to write a formula that looks up the values from the latest date before the current date for the same ID field.</p>
  
  <p>For example, I want to derive the PreVal column using the formula. is this possible in Excel?</p>
  
  <pre><code> DATE       ID    Val   PreVal
  2015-01-01   A    10     -
  2015-01-02   B    15     -
  2015-01-05   A    20    10
  2015-01-06   A    15    20
  2015-01-25   B    90    15
  </code></pre>
  
  <p>Thanks in advance.</p>