Aggregating data

To create impactful data models in Tableau, it is important to understand the level of detail in your data sources. In the previous sections of this chapter, we looked at sales data. This sales data had a row for every product sold in each sales transaction. That is, if a customer had an order that had 11 products in it, that would generate 11 rows of data. That creates the level of detail of the data source.

In the previous section of this chapter, we pivoted data to create a row of sales targets for each country for each month. This defines the level of detail of the data.

For an analyst, understanding the level of detail is essential to know what answers you can get from your data model. As someone creating data models, you need to understand the level of detail when combining data sources into a single data model. To join two or more data sources into a single data model, they typically need to be at the same level of detail.

Let’s imagine that...