题解 | 查找在职员工自入职以来的薪水涨幅情况

SELECT
    emp_no,
    end_sal - start_sal AS growth # 工资差
FROM(
    SELECT
        e.emp_no,
        salary AS start_sal, # 入职工资
        end_sal # 当前工资
    FROM employees e
    JOIN salaries s
    ON e.emp_no = s.emp_no AND e.hire_date = s.from_date # 入职工资条件
    JOIN(
        SELECT
            emp_no,
            from_date,
            salary AS end_sal # 当前工资表
        FROM salaries
        WHERE to_date = '9999-01-01' # 在职条件
    ) AS tb1
    ON tb1.emp_no = e.emp_no
) AS tb2
ORDER BY growth ASC # 升序条件