表：Logs

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+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| id          | int     |
| num         | varchar |
+-------------+---------+
在 SQL 中，id 是该表的主键。
id 是一个自增列。

找出所有至少连续出现三次的数字。

返回的结果表中的数据可以按 任意顺序 排列。

结果格式如下面的例子所示：

示例 1:

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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。
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SELECT DISTINCT num AS ConsecutiveNums
FROM (
    SELECT num,
           LAG(num,1) OVER (ORDER BY id) AS pre1,
           LAG(num,2) OVER (ORDER BY id) AS pre2
    FROM Logs
) AS t
WHERE num = pre1 AND num = pre2;

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SELECT DISTINCT l1.num AS ConsecutiveNums
FROM Logs l1
JOIN Logs l2 ON l2.id = l1.id + 1 AND l2.num = l1.num
JOIN Logs l3 ON l3.id = l1.id + 2 AND l3.num = l1.num;