leetcode 180. Consecutive Numbers数据库

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.

+-----------------+
| ConsecutiveNums |
+-----------------+
| 1               |
+-----------------+

题目链接：https://leetcode.com/problems/consecutive-numbers/

# Write your MySQL query statement below
#select Num as ConsecutiveNums from Logs where

#select Num, count(Id) as counter from Logs group by Num where counter >= 3

select distinct Num as ConsecutiveNums from
    (select 
        Num,
        @count := if(@prev = (@prev := Num), @count + 1, 1) as counter 
    from 
        Logs,
        (select @prev := -1, @count := 1) as temp
     ) as result
where counter >= 3;