The groupings of functions mentioned earlier are important for understanding what kind of functionality is possible. However, the most fundamental way to understand calculations in Tableau is to think of three different levels of calculation:
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
Table calculations: These calculations are performed on the table of aggregate data that has been returned by the data source to Tableau
Row-level and aggregate-level calculations are processed as part of the query executed by the underlying source data engine. Row-level calculations are computed for each row of the source. Aggregate calculations are also computed at the data source, but the calculation is at an aggregate level. Table calculations are not calculated as part of the query to the...