The groupings of functions we mentioned previously are important for understanding what kind of functionality is possible. However, the most fundamental way to understand calculations in Tableau is to think of four major types of calculations:

• Row-level calculations: These calculations are performed for every row of underlying data.
• Aggregate-level calculations: These calculations are performed at an aggregate level, which is usually defined by the dimensions used in the view.
• Level of detail calculations: These special calculations are aggregations that are performed at a specified level of detail, with the results available at the row level. We'll cover these in detail later in this chapter.
• Table calculations: These calculations are performed at an aggregate level on the table of aggregate data that has been returned by the data source to Tableau.

In this chapter, we'll take a close look at three of the four main types of calculations in Tableau: row level, aggregate level, and level of detail calculations. We'll dive into table calculations in detail in the next chapter, Chapter 5, Diving Deep with Table Calculations.