MySQL Updates from multiple tables

I always need to do JOINED updates in MySql amd the documentation on their site doesn’t help a whole lot. Then I always forget what the exact phrase to google for. (Joined updates, multi-table updates, updating from one table to another, etc..) I found some great examples over on The Electric Toolbox that makes it dead simple.

So I am posting it here as a reminder and for anyone else wondering how to do it.