力扣MYSQL练习

176编写一个 SQL 查询，获取 Employee 表中第二高的薪水（Salary）。

select IFNULL((SELECT distinct salary

       from employee

       order by salary desc

       limit 1,1),NULL)AS SECONDHIGHESTSALARY;

select max(salary) as SecondHighestSalary

from employee

where salary not in (select max(salary) from employee);

别人的解法，先去重，再count，这样效率好很多，，我那解法巨慢。

select Score,

(select count(*) from(select distinct Score s from Scores) temp  where s>=Score) as Rank

from Scores

order by Score desc