AGGREGATE FUNCTIONS
As you saw in the previous chapter, each individual mark in your visualization typically displays the aggregated value of a measure—aggregated across all the underlying rows in the data table associated with that mark. When working with a live connection, this aggregation can often be calculated by the database server, meaning only the aggregated values need to be sent to Tableau. If you are familiar with SQL, you will notice that several of the aggregation functions in Tableau have similar equivalents in SQL.
By default, Tableau uses Sum as the aggregation. But this is not always the most appropriate way to aggregate the data. If you need to use a different function, click the small arrow when hovering over the measure used in your view. In the menu, go to Measure (Sum), and select the aggregate function that works best for your use case (see Figure 4.1).
Figure 4.1 Setting the aggregate function.
The types of aggregation supported by Tableau include the...
