[smt88]

If you need a relational schema (and you usually do), then you should use Postgres. Don't make it complicated for no reason. It can also store documents as JSONB.

If you aren't certain that you need a graph DB, don't use one.

What do you mean by advanced SQL? The language itself is simple once you understand subqueries. The underlying math can be hard, but modern RDBMS abstract a lot of the performance considerations away by optimizing your queries for you.

[slinger]

> What do you mean by advanced SQL? I mean, understanding how to write your query using the right database features to get the best performance and understand query plans so that you can optimize slow queries.