5 Replies Latest reply on Jul 31, 2017 11:46 PM by Marta Roche

    Why do date dimensions default to YEAR?

    David Li

      Hi folks! I've been teaching some Tableau classes recently, and I'm racking my brain to explain to my students why date fields behave the way they do. I've read that one of Tableau's main goals is to ensure consistency and predictability in behavior, so the default behavior for dates baffles me.


      Let me give you an example. Let's say that I have some data with a discrete date dimension. If I double-click or left-click-and-drag this field to the columns shelf, I get YEAR(Date) as the default. Why? This is so bizarre, because Tableau does it even if the dates don't span different years. It even does it when there is only one distinct date in the field! It's silly to assume that most users will want to see their dates broken down by year by default, regardless of the underlying metadata.


      Of course, we can get around this by right-click-and-dragging the date field and choosing to display discrete dates, but that's where the predictability issue comes into play. I don't have to do this for any other dimension data type; only dates. Why wouldn't it show discrete dates by default? It displays all other dimensions discretely. I thought it might be because there could potentially be too many members, but other fields just warn users about this. Why not do the same thing with dates?


      Things get even weirder when I try to change the YEAR(Date) pill to discrete. If I right-click the pill and try to change it to either "Exact Date" or "Day", it automatically turns into a green continuous pill. Why? I can kind of understand why picking "Day" might do this, since DAY() is kind of like a function, but "Exact Date" is not; it's just the discrete date. I have to edit the pill again to set it back to discrete.


      I'd love it if someone could elucidate the thought process behind this seemingly bizarre design choice.