title: Selecting max value across columns opposed to across rows
body: <p>I am attempting to select the max value within separate columns per a dimension listed in a row as so;</p>
  
  <pre><code> Input Dataset
   Person|Date#1  |Date#2  |Date#3  |Date#4
   ------+--------+--------+--------+---------
   Matt  |12/01/18|01/15/19|02/15/19|04/15/18
   Dave  |01/15/18|01/02/19|03/15/19|11/01/19
  
  
  Desired result
  
  
   Input Dataset
   Person|Max Date|
   ------+--------+
   Matt  |02/15/19|
   Dave  |11/01/19|
  </code></pre>