LeetCode Database

+----+-------+--------+--------------+
| Id | Name  | Salary | DepartmentId |
+----+-------+--------+--------------+
| 1  | Joe   | 85000  | 1            |
| 2  | Henry | 80000  | 2            |
| 3  | Sam   | 60000  | 2            |
| 4  | Max   | 90000  | 1            |
| 5  | Janet | 69000  | 1            |
| 6  | Randy | 85000  | 1            |
| 7  | Will  | 70000  | 1            |
+----+-------+--------+--------------+

select name, salary, departmentID
from Employee as e1
where 2 >= (
	select count( distinct e2.salary)
	from Employee as e2
	where e2.departmentID = e1.departmentID and
		e2.salary > e1.salary
)
;

   +------+------------+-----------+
| id   | visit_date | people    |
+------+------------+-----------+
| 1    | 2017-01-01 | 10        |
| 2    | 2017-01-02 | 109       |
| 3    | 2017-01-03 | 150       |
| 4    | 2017-01-04 | 99        |
| 5    | 2017-01-05 | 145       |
| 6    | 2017-01-06 | 1455      |
| 7    | 2017-01-07 | 199       |
| 8    | 2017-01-08 | 188       |
+------+------------+-----------+

   select distinct t1.* from stadium as t1, stadium as t2, stadium as t3
where t1.people >= 100 and t2.people >= 100 and t3.people >= 100
and 
(
   	(t1.id = t2.id - 1 and t1.id = t3.id - 2)
   	or 
   	(t1.id = t2.id + 1 and t1.id = t3.id + 2)
   	or 
   	(t1.id = t2.id - 1 and t1.id = t3.id + 1)
)
order by t1.id;