#案例：查询员工编号最小且工资最高的员工信息

SELECT *
FROM employees
WHERE (employee_id,salary)=(

    SELECT MIN(employee_id),MAX(salary)
    FROM employees
);

由以下代码演变而来

SELECT *
FROM employees
WHERE employee_id=(
    SELECT MIN(employee_id)
    FROM employees
) AND salary=(
    SELECT MAX(salary)
    FROM employees
);