获取当前(to_date=‘9999-01-01’)薪水第二多的员工的emp_no以及其对应的薪水salary
CREATE TABLE salaries
(
emp_no
int(11) NOT NULL,
salary
int(11) NOT NULL,
from_date
date NOT NULL,
to_date
date NOT NULL,
PRIMARY KEY (emp_no
,from_date
));
--order by + group by
select emp_no , salary
from salaries
where to_date = '9999-01-01'
group by salary
order by salary desc
limit 1,1;
-- order by + 子查询distinct
select emp_no , salary
from salaries
where salary = (
select distinct salary
from salaries
where to_date = '9999-01-01'
order by salary desc
limit 1,1);