To show all the days in the month regardless of there being data or not, try right clicking on your date on the columns shelf and changing the field to continuous rather than discrete. Still trying to understand the other part of the question.
Thank you Michael. I changed the date to Continuous, but I still need to work on the other part. I'll try to explain what I'm looking for... basically I want to count how many shipments were late. So if the Ship Date is > Required date, then for each day that passed between the Required Date (the date it was supposed to ship) and the (actual) Ship Date, that shipment counts as 1. So if the product was supposed to ship Monday, but didn't ship until Wednesday, you would see a count of 1 on Monday, and 1 on Tues, and 1 on Wed. And I would like to see the last 30 days history.
My calculated field "LateOrNot" shows the 1's when the shipments were late (and 0's if not), but I can't get that field to sum for each day - Tableau wants to sum them all on the REQD_Dt.
Thank you again!