Leetcode 180. 连续出现的数字

编写一个 SQL 查询，查找所有至少连续出现三次的数字。

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

例如，给定上面的 Logs 表， 1 是唯一连续出现至少三次的数字。

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

思路：id连续，且对应的num相等，即联结判断三重ID和Num是否相等

select DISTINCT l1.Num as ConsecutiveNums 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