How to Write a Common Table Expression in MySQL

Common table expressions (CTEs) are a great way to break up complex queries. MySQL started supporting this in version 8. Here's a simple query to illustrate how to write a CTE:

with beta_users as (
  select *
  from users
  where beta is true
)
select events.*
from events
inner join beta_users on beta_users.id = events.user_id;

You can find more complex examples of using CTE's in How to Avoid Gaps in Data in MySQL and in Calculating Cumulative Sums in MySQL.