jbradley311

Tableau user here. It took me a while to get my head around the concept of'data blending' as the documentation a while back was aimed at non-technical users (the beauty of Tableau is that it's so easy to pick up and start making data visualisations with). I'm not sure about Alteryx, but in Tableau, a blend is fundamentally just a left outer join (so everything in the left table is always returned by the query). The clever bit is that Tableau will aggregate the data in the left table based on the fields (and therefore level of granularity) you choose from the right table(s) before the join is done. Hence, data blending is very useful when you want to join datasets that are at different levels of granularity. One thing to keep in mind though is, as an outer join is done between the left tables and right table(s), performance can quickly reduce as the sizes of the table(s) in your query get bigger.