deeprun

Consecutive Numbers

 문제 설명

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| id          | int     |
| num         | varchar |
+-------------+---------+
id is the primary key for this table.

 입출력 예

Example 1:

Input: 
Logs table:
+----+-----+
| id | num |
+----+-----+
| 1  | 1   |
| 2  | 1   |
| 3  | 1   |
| 4  | 2   |
| 5  | 1   |
| 6  | 2   |
| 7  | 2   |
+----+-----+
Output: 
+-----------------+
| ConsecutiveNums |
+-----------------+
| 1               |
+-----------------+
Explanation: 1 is the only number that appears consecutively for at least three times.

 Oracle Query

SELECT DISTINCT 
	l1.Num As ConsecutiveNums
FROM Logs l1
JOIN Logs l2 ON l1.Id = l2.Id-1
JOIN Logs l3 ON l2.Id = l3.Id-1
WHERE l1.Num = l2.Num
	AND l2.Num = l3.Num;

* 참고 링크 : https://leetcode.com/problems/consecutive-numbers/discuss/185886/Self-Join-Twice-(681-ms-faster-than-100.00-of-Oracle-online-submissions-for-Consecutive-Numbers.)

 출처

https://leetcode.com/problems/consecutive-numbers/