How important is learning SQL if I can use sequelize?

I know that sequelize is not an ideal replacement for SQL queries, and I don’t doubt that learning SQL is beneficial, but I have limited learning time right now, so I want to make sure I focus it properly.

In the past I have used MongoDB, but in the latest project I have for work, we are using mySQL. I use sequelize to communicate with the database, and so far so good. I was able to make models, insert and retrieve info from my tables, create a join table and edit information in the join table. All without knowing any SQL at all.

What I found hardest (aside from going through the sequelize documentation :dizzy_face: ) was wrapping my head around how to build relations between my items. So on a conceptual level, I still find it hard to think in terms of relational database.
I looked at some SQL tutorials, but they seem to be all about the syntax. How valuable would that be to learn? Or are there any other resources that are useful to learn relational databases without the syntax?

I think it would be best to know how a database works before using an ORM for it. You said you used Mongo previously, did you use MongoDB itself or did you use Mongoose? If you want a complete understanding of what you are doing instead of just copy-pasting code, I think it would be best to understand at least the basics of relational databases and how SQL works.