title: Compare two SQL Server columns with a value and insert output in third column
body: <p>I have two columns WL-Value and RF-Value, if both have any value then we have insert value in third column "Final". If those any columns have 0 or null value then only need to take column heading text which column have value.</p>
  
  <p>I need query for inserting value in "Final" column after comparing WL-Value and RF-Value according to their values.</p>
  
  <pre><code>------------------------------------------------------------------------  
  ID   |    WL-Value      |            RF-Value        |        Final    |
  ------------------------------------------------------------------------
  1         0                           243000                    RF
  2        254365                        0                        WL
  3        2478954'                     2874269                   RF,WL
  4         0                             0                       Null
  5        Null                           0                       Null
  </code></pre>
  
  <p>Query require for "Final" column after checking other two columns</p>