Leetcode 180: Consecutive Numbers

180. Consecutive Numbers

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  • Total Submissions: 52571
  • Difficulty: Medium
  • Contributors: Admin

Write a SQL query to find all numbers that appear at least three times consecutively.

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

For example, given the above Logs table, 1 is the only number that appears consecutively for at least three times.

 

Code

# Write your MySQL query statement below
select distinct l1.Num as ConsecutiveNums
from Logs l1, Logs l2, Logs l3
where l1.Id = l2.Id -1 and l1.Id = l3.Id-2 and l1.Num = l2.Num and l1.Num = l3.Num

 

Idea

For this kind of problems, you need to have multiple instances of the same table (Logs l1, Logs l2, Logs l3).

 

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