Combining and joining data
Thus far, we have been focused on accessing and retrieving data from individual data sources with minimal data transformation. However, in addition to accessing data, one of the strengths of the M language is the ability to transform and combine that data. This provides the ability to combine data from multiple sources together such as merging inventory data with sales data or combining customer data from multiple CRM systems. Therefore, we will briefly cover five basic functions that allow us to combine and merge our data together. These five functions are:
Table.Combine
Table.NestedJoin
Table.Join
Table.FuzzyNestedJoin
Table.FuzzyJoin
As you read this section, it will be helpful to reference Rick de Groot’s Join Types Cheat Sheet, which can be found here: https://gorilla.bi/power-query/join-types/. For ease of reference, the cheat sheet is included here:
Figure 3.13: Output of Table.NestedJoin...