SQL ntile

NTILE (number) OVER (PARTITION BY partition_col ORDER BY order_col)

CREATE TABLE employees (
    emp_id INT,
    emp_name VARCHAR(50),
    salary DECIMAL(10,2)
);

INSERT INTO employees (emp_id, emp_name, salary)
VALUES 
(1, 'Alice', 50000),
(2, 'Bob', 60000),
(3, 'Charlie', 70000),
(4, 'David', 80000),
(5, 'Eva', 90000),
(6, 'Frank', 100000),
(7, 'Grace', 110000),
(8, 'Henry', 120000);

SELECT 
    emp_name,
    salary,
    NTILE(4) OVER (ORDER BY salary) AS salary_level
FROM employees;