Dealing with NULLs
When working with calculated fields, it is important to understand what NULLs are and how to deal with fields that have NULL values.
A NULL is a missing value. It is an indeterminate value. A NULL is not:
- a zero
- a space
- an empty string
Whenever there is an operation between a field that has a value and a field that has a NULL, the result is always a NULL. When you add 1 to nothing, what is the result? Indeterminate. When you concatenate a first name to an unknown value, what is the result? Indeterminate—we don't know.
Let's take the following data set:
Once you connect this Excel file to Tableau, the initial connection screen will look ...
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