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               |
+-----------------+

Soluton

SELECT DISTINCT
    a.Num AS ConsecutiveNums
FROM
    LOGS a,
    LOGS b,
    LOGS c
WHERE
    a.Id + 1 = b.id
AND b.Id + 1 = c.Id
AND a.num = b.num
AND b.num = c.num;