title: Table Calc - with IF statement? - Tableau
body: <p>We have YTD data only. I've been trying to get a MTD running across the table.
  So I thought I can run a Table calculation type - "Difference From" previous month.</p>
  
  <p>This works well except for the first month of the year.
  Jan MTD = Jan YTD   NOT   Jan YTD less Dec YTD
  So January numbers are never right.</p>
  
  <p>Is there a way to say, If month = "Jan" don't perform the table calc?</p>
  
  <p>regards
  Gem</p>