Question
In Power Query Editor, you have three queries named ProductCategory, ProductSubCategory, and Product.
Every Product has a ProductSubCategory.
Not every ProductSubCategory has a parent ProductCategory.
You need to merge the three queries into a single query. The solution must ensure the best performance in Power Query.
How should you merge the tables? Each join kind may be used once, more than once, or not at all.
Explanation
Every product has a subcategory, so an inner join between Product and ProductSubCategory keeps every product and is the cheapest join to evaluate. Not every subcategory has a parent category, so ProductSubCategory must be joined to ProductCategory with a left outer join; an inner join there would drop subcategories without a category and the products in them. Full outer and right joins would add category rows with no products, and anti joins return only non-matching rows.
