使用CASE的条件MySQL查询

SELECT 
    employee_id, 
    department,
    salary,
    CASE department
        WHEN 'HR' THEN salary * 0.05
        WHEN 'Engineering' THEN salary * 0.10
        ELSE salary * 0.02
    END AS bonus
FROM employees;

SELECT 
    employee_id, 
    salary,
    CASE 
        WHEN salary > 100000 THEN 'A'
        WHEN salary > 75000 AND salary <= 100000 THEN 'B'
        WHEN salary > 50000 AND salary <= 75000 THEN 'C'
        ELSE 'D'
    END AS rating
FROM employees;

SELECT 
    order_id, 
    status,
    amount,
    CASE 
        WHEN status = 'Cancelled' THEN 0
        WHEN status = 'Pending' AND amount > 1000 THEN 0.10
        WHEN status = 'Pending' THEN 0.05
        ELSE 0
    END AS discount
FROM orders;