How do you handle null and other special values in Tableau?

 In Tableau, you can handle null and other special values using various techniques and functions. Here are some common approaches:

1. Filtering: You can filter out null or specific special values from your data by applying filters. To do this, right-click on the dimension or measure field in the Data pane and select "Filter." In the filter dialog, you can specify conditions to exclude null or other special values from your analysis.
2. Calculated Fields: Tableau allows you to create calculated fields to handle null and special values. You can use functions like ISNULL, IFNULL, or NULLIF to check for null values and replace them with a default value or perform other operations. For example, you can create a calculated field like IFNULL([Sales], 0) to replace null values in the "Sales" field with zero.
3. Coalesce Function: The COALESCE function in Tableau allows you to select the first non-null value from a list of fields or expressions. It can be useful when dealing with multiple fields that could contain null values. For example, COALESCE([Field1], [Field2], [Field3]) will return the first non-null value among Field1, Field2, and Field3.
4. Data Source Level Handling: Tableau provides options to handle null and special values at the data source level. You can use data source filters or custom SQL queries to exclude or transform specific values before bringing the data into Tableau.
5. Data Blending: If you are blending data from multiple sources, you can use data blending techniques to handle null or special values. Tableau allows you to control how null values are handled during data blending by configuring the data relationship and joining options.
6. Custom Formatting: You can define custom formatting for null and special values to make them visually distinct in your visualizations. For example, you can set a specific color or text for null values to highlight them.

These are some of the common techniques to handle null and special values in Tableau. The approach you choose depends on the specific requirements of your analysis and the nature of the data you are working with.