Found a few that looked decent. I took a few database courses during my undergrad but have only recently began to use that education in building a webapp database. I like using MySQL, but if you just want general database education then look at other frameworks and languages as well.
Coursera: https://www.coursera.org/learn/sql-data-science
Udemy: https://www.udemy.com/course/the-ultimate-mysql-bootcamp-go-from-sql-beginner-to-expert/
edX: https://www.edx.org/learn/databases
I am a big fan of Udemy, courses are usually never more than $15 and you keep them forever, and good ones continue to be updated on a regular basis.