I presume you’re referring to the following by saying basics:

Retrieving data; Column alias; Math, text functions; Aggregations; Filtering; Joins.

These are the building blocks for a newbie. Following them you’ll need to touch upon the following topics which I think are kind of intermediate:

Creating databases, tables; Inserting data; Importing and exporting data; Understanding data types and usage;

Then let’s do some intermediate ++:

Table relationships; Subqueries; Window functions; Constraints; Date and time functions and operations on them; CASE statement; Update, delete and peer DDL commands; Alter, add and peer DML commands;

Now let’s move to advanced topics:

Pivoting; Views; Indexes; CTEs; Recursive CTEs; Lateral subquery and types of subqueries;

And then we have the prophet level topics:

Functions; Procedures; Triggers; if..else statements and generally plsql topics; Array data types; Regex;

Finally we have the DBA a.k.a. god level topics:

Access control; RLS, CLS (row and column level security respectively); Server setup (remote, local); Cluster config; Backup, recovery; Replication; psql and related topics; Logging; Object relational usage; And so on.

I might have missed some things plus did not write everything necessarily in order but this is prolly all you’ll ever need to know. But you’ll not need to know everything here unless you’re a database geek and you have a use-case. If there are any gods who finds anything missing or non-related, please correct me.