Are you able to write queries?

Writing queries is a core skill for any developer working with relational databases. A basic SELECT statement retrieves data from one or more tables, e.g., SELECT * FROM employees WHERE department = 'Sales';. You can filter results with WHERE, sort them with ORDER BY, and limit the number of rows with LIMIT. JOINs combine rows from multiple tables based on a related column: SELECT e.name, d.name FROM employees e JOIN departments d ON e.dept_id = d.id;. Aggregations like COUNT, SUM, AVG, MIN, and MAX are performed with GROUP BY and HAVING clauses. Subqueries allow you to nest a SELECT inside another SELECT, and common table expressions (WITH clauses) can make complex queries more readable. Understanding indexes, execution plans, and how to write efficient queries is also important. Practice by modeling a small schema, writing queries to answer business questions, and using EXPLAIN to analyze performance.