LeetCode数据库题目
题目
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
- 查询目标：Num (As ConsecutiveNums)
- 查询范围：Logs表
- 查询条件：所有至少连续出现三次的数字
解答
select distinct
l1.Num as ConsecutiveNums
from
Logs as l1,Logs as l2,Logs as l3
where
l1.Num = l2.Num and l2.Num = l3.Num and l1.Id = l2.Id -1 and l2.Id = l3.Id -1
