What is your level of knowledge of databases — queries, analytics, how large are the databases?

My database knowledge includes:

• Proficient in SQL: writing complex queries with JOINs, subqueries, and aggregate functions.
• Experience with analytical queries for extracting business metrics and reporting.
• Familiarity with query optimization and indexing to improve performance.
• Working with relational DBMSs (PostgreSQL, MySQL) and understanding their architecture.
• Experience with large databases (from several gigabytes to terabytes), including data partitioning and sharding.

For example, I can write a query for sales analysis by regions using window functions and aggregates, and optimize it for fast execution on large datasets.