What level of SQL do you know? SELECT, JOIN, window functions?

I am familiar with SQL at a level that allows me to confidently use:

• SELECT — for data retrieval with filtering, sorting, and aggregation.
• JOIN — for combining tables of various types (INNER, LEFT, RIGHT, FULL) to obtain related data.
• Window functions — for calculating aggregates and ranking within groups without grouping the entire dataset.

For example, I can write queries with multiple JOINs and use window functions for analytics, such as calculating moving sums or ranking records by categories.