The answer is Yes. You can learn MongoDB without learning SQL. As Shreyansh said MongoDB is a schemaless and document oriented database. It stores your data in bson format. So, you just need to be little bit familiar with JSON to understand how the data is going to be stored in collections.

Also, have a look at university.mongodb.com you can register for free classes

I don't have a C++ background but Mongo has first class driver support in pretty much every major language out there. Its also far more flexible than traditional sql (for better or for worse) so you can get up and running quickly. Heres a link to the C++ docs on the mongo site:

docs.mongodb.org/ecosystem/drivers/cpp

While you're there, give a look around. Their documentation is quite good and very clear. I think you'll find it very easy to pick up.

Well, you can. Mongo is something we call a NoSQL database; or Not-only SQL. Essentially it's a schemaless database, so you have the freedom to store whatever you want.

I wouldn't go into the gory details, because there are enough already on Hashnode. But, I'd recommend you learn both. Some places, you need to use MySQL (RDMS), and sometimes NoSQL.

What I'd say is that you do a small, tiny course in SQL, then a fully fledged course in Mongo.