Experience working with PostgreSQL? How deep?

Experience with PostgreSQL may include:

• Creating and optimizing complex SQL queries, including JOINs, subqueries, window functions.
• Designing database schemas using indexes, constraints, triggers.
• Working with PostgreSQL extensions, such as PostGIS for geospatial data.
• Performance tuning: analyzing execution plans, configuring server parameters.
• Using transactions and managing locks to ensure data integrity.

Example of a simple query with a window function:

SELECT user_id, order_date, SUM(amount) OVER (PARTITION BY user_id ORDER BY order_date) AS running_total
FROM orders;

The depth of experience depends on the tasks: from basic CRUD to complex analytics and administration.