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);

178编写一个 SQL 查询来实现分数排名。如果两个分数相同，则两个分数排名（Rank）相同。请注意，平分后的下一个名次应该是下一个连续的整数值。换句话说，名次之间不应该有“间隔”。

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