Millisel tasemel sa tead SQL-i? SELECT, JOIN, akna funktsioonid?

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

• SELECT — data retrieval with filtering, sorting, and aggregation.
• JOIN — combining tables of different types (INNER, LEFT, RIGHT, FULL) to obtain related data.
• Window functions — to compute aggregates and rankings by groups without grouping the entire selection.

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.