title: Use one date filter on multiple columns in tableau
body: <p>I do have data set with multiple date columns with different values of dates across all the months and years. I want to create a report wherein when I select a Year, I want to list the count of dates across each months on that year. Based on one Year field selection, how can I apply filter across different date fields to display the counts for that particular year</p>
  
  <p>Lets say we have the data set like this</p>
  
  <pre><code>Date 1          Date 2 
  1/3/2017        NA
  1/23/2017      1/23/2017
  1/14/2017      1/16/2017
  2/2/2017       2/3/2017
  NA             2/21/2017
  3/1/2017        NA
  3/3/2017       3/21/2017
  .
  .
  .
  12/1/2017       12/12/2017
  </code></pre>
  
  <p>My result should look like this when I pick the year 2017</p>
  
  <pre><code>    Date 1    Date 2
  Jan      3        2
  Feb      1        2
  Mar      2        1
  .
  .
  Dec      1        1
  </code></pre>
  
  <p>I was able to apply filter on one column but when I try to apply on other columns, I am not getting desired result</p>