我在MySQL中有两个表.在每个表中,保存了具有其MAC地址和状态区域信息的设备.
这些状态确实在某些时间戳记(startTime,endTime)及其持续时间(endTime-startTime)处开始和结束,并且是由某些ID引起的.
现在,我想找到某些事件“移动”和“负载”之间的重叠部分,这些重叠部分以天为单位,如下所示:
sum of time, when movement took place (value in the fiddle: 421)
sum of time, when load took place (value in the fiddle: 520)
sum of time, when movement and load took place (value in the fiddle: 391)
查询结果应如下所示:
ID DATE ALL_MOVEMENT ALL_LOAD LOAD_MOVEMENT
00:50:c2:63:10:1a October, 29 2012 00:00:00+0000 421 520 391
00:50:c2:63:10:1a February, 22 2013 00:00:00+0000 421 520 391
00:50:c2:63:10:1b February, 22 2013 00:00:00+0000 181 220 181
我在这里准备了小提琴:http://sqlfiddle.com/#!2/c210c
更新:在这里可以看到一个小提琴,它以不同的表结构提供了我想要的东西:
http://sqlfiddle.com/#!2/31b94/1
解决方法:
我不太了解数据集与结果集之间的关系,但在我看来,您或多或少需要这样的东西…
SELECT m.id
, DATE(FROM_UNIXTIME(m.starttime))Date,SUM(m.duration) all_movement
, SUM(l.duration) all_load
FROM move_table m
JOIN load_table l
ON l.id = m.id
AND l.endtime > m.starttime
AND l.starttime < m.endtime
GROUP
BY m.id
, DATE(FROM_UNIXTIME(m.starttime));
+-------------------+------------+--------------+----------+
| id | Date | all_movement | all_load |
+-------------------+------------+--------------+----------+
| 00:50:c2:63:10:1a | 2012-10-29 | 391 | 520 |
| 00:50:c2:63:10:1a | 2013-02-22 | 391 | 520 |
| 00:50:c2:63:10:1b | 2013-02-22 | 181 | 220 |
+-------------------+------------+--------------+----------+
顺便说一句,在这种情况下,持续时间似乎是多余的,因为(例如)SUM(m.endtime-m.starttime)将为您提供相同的结果.