Expensive Calculations. hmmm. what does that mean?
How do I know what is going to be expensive? Yes, fair question. I would ask you to think what you are asking the calc to do.
Here is an example
I want to create a calculation that creates a hierarchy.
Let’s say I have the following Status values on a field
On you want to create field called “High Level Status” that combines these values to a higher level, like this
You can create this calculation like so
which is a terrible idea.
Why? Because you are asking each row to be evaluated 11 times for each condition.
The same calc could be written various ways, like
This is basically same business logic but once a value has been met, Tableau isn’t going to keep checking if the value in the row matches another value mentioned in the calc.
Better still, you could just do
this will be a much more efficient manner of doing the same calc.
BTW, the IN operator just got released on 2020.3