Leetcode No.180 Consecutive Numbers

Write a SQL query to find all numbers that appear at least three times consecutively.

+----+-----+
| Id | Num |
+----+-----+
| 1  |  1  |
| 2  |  1  |
| 3  |  1  |
| 4  |  2  |
| 5  |  1  |
| 6  |  2  |
| 7  |  2  |
+----+-----+

For example, given the above Logs table, 1 is the only number that appears consecutively for at least three times.

+-----------------+
| ConsecutiveNums |
+-----------------+
| 1               |
+-----------------+

如下答案摘自：https://discuss.leetcode.com/topic/22606/simple-solution

做者：lemonxixi ，若有侵權，請聯繫本人刪除。

Select DISTINCT l1.Num from Logs l1, Logs l2, Logs l3 
where l1.Id=l2.Id-1 and l2.Id=l3.Id-1 
and l1.Num=l2.Num and l2.Num=l3.Num