MySQL 擷取連續範圍，mysql擷取範圍

MySQL 擷取連續範圍，mysql擷取範圍

1、未經處理資料

2、把running_number轉成資料，並加上一列有序數字

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;

3、running_number與有序資料的差，差(diff)相同的的running_number說明是連續的

SELECT running_number,rn,running_number-rn diffFROM (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;

4、根據差來分組，並獲得相關差的最小及最大running_number，就形成了連續範圍

select min(c.running_number) min,max(c.running_number) maxfrom(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;

5、參考《MySQL技術內幕：SQL編程》 2.6.2連續範圍問題