# 对所有员工的薪水按照salary降序进行1-N的排名，要求相同salary并列，且按照emp_no升序排列
# 方法一：分出两张相同的salaries表,s1，s2通过比较salary，得出s2.salary在s1.salary存在的个数，即名次即名次；
SELECT s1.emp_no, s1.salary, count(distinct s2.salary) AS rank_t
FROM salaries AS s1, salaries AS s2
WHERE s1.to_date = "9999-01-01" AND s2.to_date = "9999-01-01" AND s1.salary <= s2.salary
GROUP BY s1.emp_no
ORDER BY s1.salary DESC, s1.emp_no ASC