题解 | #对所有员工的薪水按照salary进行按照1-N的排名#

还有一种写法，作用相当于是窗口函数 DENSE_RANK()

SELECT emp_no,salary,
CASE 
WHEN @prevRank = salary THEN @curRank 
WHEN @prevRank := salary THEN @curRank := @curRank + 1
END AS t_rank
FROM salaries, 
(SELECT @curRank :=0, @prevRank := NULL) r
ORDER BY salary desc,emp_no