What format did you work with databases in? Tell us about your experience writing SQL queries.

In working with databases, I primarily used relational DBMSs such as PostgreSQL and MySQL. The interaction format is SQL queries, which allow extracting, updating, and analyzing data.

My experience with writing SQL queries includes:

• Simple SELECTs with filtering and sorting
• JOINs for table merging
• Aggregations with GROUP BY
• Subqueries and window functions
• Query optimization using indexes

An example query to get a list of users with the number of orders:

SELECT u.id, u.name, COUNT(o.id) AS orders_count
FROM users u
LEFT JOIN orders o ON u.id = o.user_id
GROUP BY u.id, u.name
ORDER BY orders_count DESC;

This approach allows efficient work with data on the frontend, obtaining necessary information for display and analysis.