Best way to save active and not-active items for Tableau

Question

I have a DB of temperatures in RedShift.

The fact table contains the following columns:

1. measurement_date
2. measurement_type
3. measurement_category
4. temperature
5. humidity
6. brightness
7. etc...

On some days (due to hardware problems) measurement may be missing.

I would like to be able to efficiently see in Tableau which days I had no measurements on, for which measurement_types and for which measurement_categories.

Could you please suggest what would be the "best practice approach" to implement something like this in Tableau?

Thanks!

Answer 1

In Tableau, you can check for null values with ZN expression (see here) or ISNULL expression (see here).

Then, you can create Calculated Fields for the subset of Null or Non-Null values, with this kind of structure

IF ZN([temperature]) = 0 THEN "show" END

or

IF ISNULL([temperature]) THEN "show" END

This gives you a new variable for which you can filter.

You can also string multiple variables in order to get more specific scenerios:

IF ISNULL([temperature]) AND [measurement_type] = "whatever" THEN "show" END

Read more about it here.