MySQL experts joined DBTA's webinar, 'Best Practices for Accelerating your MySQL Data,' to examine architectural tips and best practices that can best support large-scale MySQL operations while ...

Let’s say you need to delete data from 10 tables as part of some operation. You might be tempted to run all the deletes across all the tables in a single transaction—but don’t do it.

In MySQL it's about 4 seconds vs. about 1.5 minutes. I believe MySQL is creating a temporary table with the entire contents of the subquery where as SQL Server's optimizer is doing something smarter.