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NOTE: Depending on the size of your datasets, a cross join can greatly expand the size of the output, which may increase costs in some environments.

Self Join

A self join is a join operation between a dataset and a copy of itself. For example, you can use a self-join to invert the structure of hierarchical data, such as brand-product or manager-employee.

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 supports joins between a recipe and any upstream recipe or dataset. 

    • You cannot join a recipe to itself.
    • You can join it to its source imported dataset. When a self-join is performed with a recipe connected to its source dataset, only one line connects the imported dataset with the recipe in Flow View. This is as designed.
    • You can join a recipe to any recipe upstream of it. Examples:
      • You can create an empty recipe after the recipe from which you wish to self-join. In this new empty recipe, you add the join step back to the original recipe.
      • You can insert an empty recipe between an imported dataset and the recipe where the self-join is performed. When you perform the self join in the first recipe, you join to the empty recipe you just created in between. 
      • In both examples, you can see multiple lines in Flow View to indicate the self-join. See Flow View Page.

Joins Together

The following diagram summarizes the relationships between the types of supported joins. In each venn diagram, the area of intersection is the set of records that contain shared key values.

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Join Types

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