Introduction to unions

Sometimes you might want to analyze data with the same metadata structure, but it is stored in different files. For example, sales data from multiple year's, or different months, countries, and so on. Instead of copying and pasting the data, you can union it. We already touched upon this topic in Chapter 3, Tableau Prep. A union is basically appending rows, whereas Tableau will append all the rows of columns with the same header.

Understanding union

A union can be created by drag and drop.

1. Create the union by dragging and dropping it:

2. Or right-click on the primary dataset and select Convert to Union:

3. The user also has the option to select the files them self, or use a Wildcard union:

...