Пример SQL запроса

example.sql

SELECT
    first_name,
    salary,
    CASE
        WHEN salary < 5000 THEN 'Low'
        WHEN salary >= 5000 AND salary < 10000 THEN 'Normal'
        WHEN salary >= 10000 THEN 'High'
    ELSE 'Unknown'
    END
        salary_level
  FROM employees;