问：为什么没有179题
答：因为最近在更新数据库，179不是数据库，都是按照leetcode的模块来的，不会落下的大家放心

问题

编写一个 SQL 查询，查找所有至少连续出现三次的数字。

例如，给定上面的 Logs 表， 1 是唯一连续出现至少三次的数字。

分析过程

1.查看表的所有内容

select * from logs;


2.创建2个表l1，l2看一下效果

select * 
from 
logs as l1,
logs as l2;


3.改成三个表l1，l2和l3

select * 
from 
logs as l1,
logs as l2,
logs as l3;


4.连续三个连续的数字
就是三个表的数值是一样的，并且id是连续的


select * 
from 
logs as l1,
logs as l2,
logs as l3
where
l1.Id = l2.Id - 1
and
l2.Id = l3.Id -1
and
l1.num = l2.Num
and
l2.Num = l3.Num;


5.按照要求的结果，去重，改列名

select distinct l1.Num as ConsecutiveNums
from 
logs as l1,
logs as l2,
logs as l3
where
l1.Id = l2.Id - 1
and
l2.Id = l3.Id -1
and
l1.num = l2.Num
and
l2.Num = l3.Num;

解答

select distinct l1.Num as ConsecutiveNums
from 
logs as l1,
logs as l2,
logs as l3
where
l1.Id = l2.Id - 1
and
l2.Id = l3.Id -1
and
l1.num = l2.Num
and
l2.Num = l3.Num;