The Odin Project's Node.js course project to solidify SQL database queries with standard CRUD methods, Project: Inventory Application.
I have dealt with databases with my personal project, Milknthingzz, but either I didn't realize I could write sql when interacting with databases or Ruby on Rails abstracts it away (I assume the former).
So this project will make me more comfortable with using node.js but also give me more direct experience using SQL (which will give me more confidence in using SQl with my milknthingzz project). To my knowledge writing SQL allows your application to access and query the DB much faster than any code you write ever could.