Explain the Logical Function ' ISNULL' in Tableau with Example?

In Tableau, the "ISNULL" logical function is used to check if a field or expression contains a null value. It returns a Boolean (true or false) result indicating whether the specified value is null or not.

The syntax of the "ISNULL" function in Tableau is as follows:

ISNULL(value)

Here's an example to illustrate how the "ISNULL" function works in Tableau:

Suppose you have a dataset of employees and their sales targets. However, some employees have missing or null values for their sales targets. You want to identify those employees with null sales targets.

ISNULL([Sales Target])

In this example, the "ISNULL" function is used to check if the sales target value in the [Sales Target] field is null. If the sales target value is null, the function will return true. If the sales target value is not null, the function will return false.

For instance, if an employee has a null sales target, the "ISNULL" function will return true for that employee. If another employee has a non-null sales target value, the function will return false.

The "ISNULL" function is helpful for identifying null values in Tableau calculations, data visualizations, and data analysis. It allows you to perform conditional evaluations based on the presence of null values in your data. By using the "ISNULL" function, you can handle null values appropriately and tailor your calculations or visualizations accordingly.