leetcode-SQL-180. 连续出现的数字

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| id          | int     |
| num         | varchar |
+-------------+---------+
id 是这个表的主键。

输入：
Logs 表：
+----+-----+
| Id | Num |
+----+-----+
| 1  | 1   |
| 2  | 1   |
| 3  | 1   |
| 4  | 2   |
| 5  | 1   |
| 6  | 2   |
| 7  | 2   |
+----+-----+
输出：
Result 表：
+-----------------+
| ConsecutiveNums |
+-----------------+
| 1               |
+-----------------+
解释：1 是唯一连续出现至少三次的数字。

select
    distinct a.Num as ConsecutiveNums
from Logs as a
inner join Logs as b
on a.Id=b.Id+1
inner join Logs as c
on a.Id=c.Id+2
where a.Num=b.Num and a.Num=c.Num;