What is the result of using the Append Fields Tool in Alteryx?

The Append Fields Tool in Alteryx is designed to add fields from one dataset to another, effectively creating a Cartesian join. This means that for every row in the first dataset, every row in the second dataset will be included in the output. The result is not limited to matching rows but combines all possible rows from both datasets, leading to a multiplication of the number of rows based on the sizes of the initial datasets. This is particularly useful when you want to enrich your data with multiple combinations of values from different datasets without any matching criteria.

Other join types, such as outer and inner joins, rely on matching records based on specific keys or conditions, resulting in a more filtered dataset. The append operation does not require such conditions, hence producing a Cartesian product instead.