MySQL获取连续范围

2015-07-24 09:12:47 · 作者: · 浏览: 2

1、原始数据
原始数据

2、把running_number转成数据,并加上一列有序数字

SELECT d.running_number+0 running_number,@a:=@a+1 rn FROM device_data d,(SELECT @a:=0) a 
where d.device_id=13 order by d.running_number;

加上有序数据

3、running_number与有序数据的差,差(diff)相同的的running_number说明是连续的

SELECT running_number,rn,running_number-rn diff FROM (SELECT d.running_number+0 running_number,@a:=@a+1 rn FROM device_data d,(SELECT @a:=0) a where d.device_id=13) b;

比较数据

4、根据差来分组,并获得相关差的最小及最大running_number,就形成了连续范围

select min(c.running_number) min,max(c.running_number) max from (SELECT running_number,rn,running_number-rn diff FROM (SELECT d.running_number+0 running_number,@a:=@a+1 rn FROM device_data d,(SELECT @a:=0) a where d.device_id=13) b)c group by diff; 

连续范围

5、参考《MySQL技术内幕:SQL编程》 2.6.2连续范围问题http://book.2cto.com/201211/8313.html