I have been running into issues with tableau dates. I created a string like this.
Case when campaign name="A" then '10/1/2016' when "B" then "10/3/2016" but when I pull these fields in my worksheet it displays a null. I tried to play around with different dateformat functions (without any luck).
With this email I am attaching my twbx file (start and end date are the ones I am looking to pull) and would really appreciate any help.
The data wasn't included in the TWBX (it still tried to run the query).
Regardless, I saw your calculation; did you try it with the dates YYYY-MM-DD?
When "A" Then DATE("2016-10-01")
When "B" Then DATE("2016-10-03")
When I tested it this way it worked fine.