Do you have knowledge of working with relational databases and can you write SQL queries?

Yes, I am familiar with relational databases and can write SQL queries. SQL (Structured Query Language) is used for working with data in tables: selecting, inserting, updating, and deleting data.

Example of a simple SQL query for data selection:

SELECT id, name, email FROM users WHERE active = 1 ORDER BY name;

I also know how to write more complex queries with JOINs to combine tables, use aggregate functions (SUM, COUNT), grouping (GROUP BY), subqueries, and indexes for optimization.

In Java, working with databases typically involves using JDBC or ORM frameworks (such as Hibernate), which allow executing SQL queries and managing transactions.