常见100题

select * from employees WHERE hire_date = (SELECT max(hire_date) from employees)

select * from employees 
where hire_date = (
    select distinct hire_date from employees order by hire_date desc limit 2,1
)
;

select s.* ,d.dept_no
from salaries as s 
join dept_manager as d 
on s.emp_no=d.emp_no
where s.to_date = '9999-01-01'
    and    d.to_date='9999-01-01';

SELECT e.last_name, e.first_name, d.dept_no 
FROM employees as e inner JOIN dept_emp as d
on e.emp_no = d.emp_no;

SELECT ep.last_name, ep.first_name, dp.dept_no 
FROM employees ep 
LEFT JOIN dept_emp dp
ON ep.emp_no = dp.emp_no

SELECT emp_no, COUNT(emp_no) as t
from salaries 
GROUP by emp_no HAVING t>15;

SELECT DISTINCT salary 
from salaries
where to_date = '9999-01-01' 
order by salary DESC;

select emp_no 
from employees 
where emp_no not in (select emp_no from dept_manager)

SELECT de.emp_no, dm.emp_no AS manager_no 
FROM dept_emp AS de INNER JOIN dept_manager AS dm
ON de.dept_no = dm.dept_no 
WHERE dm.to_date = '9999-01-01' AND de.to_date = '9999-01-01' AND de.emp_no <> dm.emp_no