This video related to Tableau Prep Joins & Unions, https://www.youtube.com/watch?v=f7tTlG2mfxc , shares this article ( https://www.thedataschool.co.uk/diego-parkertheinformationlab-co-uk/joins-and-unions/ ) in the description, but it shows a 404 error. I found what appears to be the referenced article here: https://www.thedataschool.co.uk/diego-parker/joins-and-unions/ .