我搜索过高和低，似乎无法找到有关如何处理我的查询的任何信息。如果我问一个愚蠢的问题，我会提前道歉，但我真的需要一些帮助。
我有一系列以不同间隔记录的值。数据如下所示：
timeStamp | RPM
2012-05-01 01:02:56 | 802
2012-05-01 01:03:45 | 845
2012-05-01 01:04:50 | 825
2012-05-01 01:05:55 | 810
2012-05-01 01:07:00 | 1000
2012-05-01 01:08:03 | 1005
2012-05-01 01:09:05 | 1145
2012-05-01 01:10:15 | 1110
2012-05-01 01:11:20 | 800
2012-05-01 01:12:22 | 812
2012-05-01 01:13:20 | 820
2012-05-01 01:14:20 | 820
2012-05-01 01:15:20 | 1200
示例中的RPM是引擎RPM。
我需要开始和结束时间戳，而RPM在800-900范围内，因为这被认为是引擎空转。我还希望能够返回每个非空闲时段的开始和结束时间。
我想要获得的结果将是：
Period | startTime | endTime | duration
Idle1 | 2012-05-01 01:02:56 | 2012-05-01 01:05:55 | 179 seconds
nonIdle1 | 2012-05-01 01:07:00 | 2012-05-01 01:10:15 | 195 seconds
idle2 | 2012-05-01 01:11:20 | 2012-05-01 01:14:20 | 180 seconds
我提前感谢您的帮助。
谢谢
答案 0 :(得分：5)
试试这个：http://www.sqlfiddle.com/#!2/e9372/1
在DB端执行此操作的优点是，您不仅可以在PHP上使用查询，还可以在Java，C＃，Python等上使用它。并且它在数据库端快速执行
select
if(idle_state = 1,
concat('Idle ', idle_count),
concat('NonIdle ', non_idle_count) ) as Period,
startTime, endTime, duration
from
(
select
@idle_count := @idle_count + if(idle_state = 1,1,0) as idle_count,
@non_idle_count := @non_idle_count +if(idle_state = 0,1,0) as non_idle_count,
state_group, idle_state,
min(timeStamp) as startTime, max(timeStamp) as endTime,
timestampdiff(second, min(timeStamp), max(timeStamp)) as duration
from
(
select *,
@idle_state := if(rpm between 800 and 900, 1, 0) as idle_state,
@state_group := @state_group +
if(@idle_state = @prev_state,0,1) as state_group,
@prev_state := @idle_state
from (tbl, (select @state_group := 0 as y) as vars)
order by tbl.timeStamp
) as x
,(select @idle_count := 0 as y, @non_idle_count := 0 as z) as vars
group by state_group, idle_state
) as summary
输出：
| PERIOD | STARTTIME | ENDTIME | DURATION |
|-----------|----------------------------|----------------------------|----------|
| Idle 1 | May, 01 2012 01:02:56-0700 | May, 01 2012 01:05:55-0700 | 179 |
| NonIdle 1 | May, 01 2012 01:07:00-0700 | May, 01 2012 01:10:15-0700 | 195 |
| Idle 2 | May, 01 2012 01:11:20-0700 | May, 01 2012 01:14:20-0700 | 180 |
| NonIdle 2 | May, 01 2012 01:15:20-0700 | May, 01 2012 01:15:20-0700 | 0 |
请在此处查看查询进度：http://www.sqlfiddle.com/#!2/e9372/1
五个步骤。
首先，将空闲与非空闲分开：
select *,
@idle_state := if(rpm between 800 and 900, 1, 0) as idle_state
from (tbl, (select @state_group := 0 as y) as vars)
order by tbl.timeStamp;
输出：
| TIMESTAMP | RPM | Y | IDLE_STATE |
|----------------------------|------|---|------------|
| May, 01 2012 01:02:56-0700 | 802 | 0 | 1 |
| May, 01 2012 01:03:45-0700 | 845 | 0 | 1 |
| May, 01 2012 01:04:50-0700 | 825 | 0 | 1 |
| May, 01 2012 01:05:55-0700 | 810 | 0 | 1 |
| May, 01 2012 01:07:00-0700 | 1000 | 0 | 0 |
| May, 01 2012 01:08:03-0700 | 1005 | 0 | 0 |
| May, 01 2012 01:09:05-0700 | 1145 | 0 | 0 |
| May, 01 2012 01:10:15-0700 | 1110 | 0 | 0 |
| May, 01 2012 01:11:20-0700 | 800 | 0 | 1 |
| May, 01 2012 01:12:22-0700 | 812 | 0 | 1 |
| May, 01 2012 01:13:20-0700 | 820 | 0 | 1 |
| May, 01 2012 01:14:20-0700 | 820 | 0 | 1 |
| May, 01 2012 01:15:20-0700 | 1200 | 0 | 0 |
其次，将更改分成几组：
select *,
@idle_state := if(rpm between 800 and 900, 1, 0) as idle_state,
@state_group := @state_group +
if(@idle_state = @prev_state,0,1) as state_group,
@prev_state := @idle_state
from (tbl, (select @state_group := 0 as y) as vars)
order by tbl.timeStamp;
输出：
| TIMESTAMP | RPM | Y | IDLE_STATE | STATE_GROUP | @PREV_STATE := @IDLE_STATE |
|----------------------------|------|---|------------|-------------|----------------------------|
| May, 01 2012 01:02:56-0700 | 802 | 0 | 1 | 1 | 1 |
| May, 01 2012 01:03:45-0700 | 845 | 0 | 1 | 1 | 1 |
| May, 01 2012 01:04:50-0700 | 825 | 0 | 1 | 1 | 1 |
| May, 01 2012 01:05:55-0700 | 810 | 0 | 1 | 1 | 1 |
| May, 01 2012 01:07:00-0700 | 1000 | 0 | 0 | 2 | 0 |
| May, 01 2012 01:08:03-0700 | 1005 | 0 | 0 | 2 | 0 |
| May, 01 2012 01:09:05-0700 | 1145 | 0 | 0 | 2 | 0 |
| May, 01 2012 01:10:15-0700 | 1110 | 0 | 0 | 2 | 0 |
| May, 01 2012 01:11:20-0700 | 800 | 0 | 1 | 3 | 1 |
| May, 01 2012 01:12:22-0700 | 812 | 0 | 1 | 3 | 1 |
| May, 01 2012 01:13:20-0700 | 820 | 0 | 1 | 3 | 1 |
| May, 01 2012 01:14:20-0700 | 820 | 0 | 1 | 3 | 1 |
| May, 01 2012 01:15:20-0700 | 1200 | 0 | 0 | 4 | 0 |
第三，对它们进行分组，并计算持续时间：
select
state_group, idle_state,
min(timeStamp) as startTime, max(timeStamp) as endTime,
timestampdiff(second, min(timeStamp), max(timeStamp)) as duration
from
(
select *,
@idle_state := if(rpm between 800 and 900, 1, 0) as idle_state,
@state_group := @state_group +
if(@idle_state = @prev_state,0,1) as state_group,
@prev_state := @idle_state
from (tbl, (select @state_group := 0 as y) as vars)
order by tbl.timeStamp
) as x
group by state_group, idle_state;
输出：
| STATE_GROUP | IDLE_STATE | STARTTIME | ENDTIME | DURATION |
|-------------|------------|----------------------------|----------------------------|----------|
| 1 | 1 | May, 01 2012 01:02:56-0700 | May, 01 2012 01:05:55-0700 | 179 |
| 2 | 0 | May, 01 2012 01:07:00-0700 | May, 01 2012 01:10:15-0700 | 195 |
| 3 | 1 | May, 01 2012 01:11:20-0700 | May, 01 2012 01:14:20-0700 | 180 |
| 4 | 0 | May, 01 2012 01:15:20-0700 | May, 01 2012 01:15:20-0700 | 0 |
第四，获取空闲和非空闲计数：
select
@idle_count := @idle_count + if(idle_state = 1,1,0) as idle_count,
@non_idle_count := @non_idle_count + if(idle_state = 0,1,0) as non_idle_count,
state_group, idle_state,
min(timeStamp) as startTime, max(timeStamp) as endTime,
timestampdiff(second, min(timeStamp), max(timeStamp)) as duration
from
(
select *,
@idle_state := if(rpm between 800 and 900, 1, 0) as idle_state,
@state_group := @state_group +
if(@idle_state = @prev_state,0,1) as state_group,
@prev_state := @idle_state
from (tbl, (select @state_group := 0 as y) as vars)
order by tbl.timeStamp
) as x
,(select @idle_count := 0 as y, @non_idle_count := 0 as z) as vars
group by state_group, idle_state;
输出：
| IDLE_COUNT | NON_IDLE_COUNT | STATE_GROUP | IDLE_STATE | STARTTIME | ENDTIME | DURATION |
|------------|----------------|-------------|------------|----------------------------|----------------------------|----------|
| 1 | 0 | 1 | 1 | May, 01 2012 01:02:56-0700 | May, 01 2012 01:05:55-0700 | 179 |
| 1 | 1 | 2 | 0 | May, 01 2012 01:07:00-0700 | May, 01 2012 01:10:15-0700 | 195 |
| 2 | 1 | 3 | 1 | May, 01 2012 01:11:20-0700 | May, 01 2012 01:14:20-0700 | 180 |
| 2 | 2 | 4 | 0 | May, 01 2012 01:15:20-0700 | May, 01 2012 01:15:20-0700 | 0 |
最后，删除分段变量：
select
if(idle_state = 1,
concat('Idle ', idle_count),
concat('NonIdle ', non_idle_count) ) as Period,
startTime, endTime, duration
from
(
select
@idle_count := @idle_count + if(idle_state = 1,1,0) as idle_count,
@non_idle_count := @non_idle_count +if(idle_state = 0,1,0) as non_idle_count,
state_group, idle_state,
min(timeStamp) as startTime, max(timeStamp) as endTime,
timestampdiff(second, min(timeStamp), max(timeStamp)) as duration
from
(
select *,
@idle_state := if(rpm between 800 and 900, 1, 0) as idle_state,
@state_group := @state_group +
if(@idle_state = @prev_state,0,1) as state_group,
@prev_state := @idle_state
from (tbl, (select @state_group := 0 as y) as vars)
order by tbl.timeStamp
) as x
,(select @idle_count := 0 as y, @non_idle_count := 0 as z) as vars
group by state_group, idle_state
) as summary
输出：
| PERIOD | STARTTIME | ENDTIME | DURATION |
|-----------|----------------------------|----------------------------|----------|
| Idle 1 | May, 01 2012 01:02:56-0700 | May, 01 2012 01:05:55-0700 | 179 |
| NonIdle 1 | May, 01 2012 01:07:00-0700 | May, 01 2012 01:10:15-0700 | 195 |
| Idle 2 | May, 01 2012 01:11:20-0700 | May, 01 2012 01:14:20-0700 | 180 |
| NonIdle 2 | May, 01 2012 01:15:20-0700 | May, 01 2012 01:15:20-0700 | 0 |
请在此处查看查询进度：http://www.sqlfiddle.com/#!2/e9372/1
<强>更新
可以缩短查询http://www.sqlfiddle.com/#!2/418cb/1
如果您注意到，则句点号串联（idle-nonIdle，idle-nonIdle等）。你可以这样做：
select
case when idle_state then
concat('Idle ', @rn := @rn + 1)
else
concat('Non-idle ', @rn )
end as Period,
min(timeStamp) as startTime, max(timeStamp) as endTime,
timestampdiff(second, min(timeStamp), max(timeStamp)) as duration
from
(
select *,
@idle_state := if(rpm between 800 and 900, 1, 0) as idle_state,
@state_group := @state_group + if(@idle_state = @prev_state,0,1) as state_group,
@prev_state := @idle_state
from (tbl, (select @state_group := 0 as y) as vars)
order by tbl.timeStamp
) as x,
(select @rn := 0) as rx
group by state_group, idle_state
输出：
| PERIOD | STARTTIME | ENDTIME | DURATION |
|------------|----------------------------|----------------------------|----------|
| Idle 1 | May, 01 2012 01:02:56-0700 | May, 01 2012 01:05:55-0700 | 179 |
| Non-idle 1 | May, 01 2012 01:07:00-0700 | May, 01 2012 01:10:15-0700 | 195 |
| Idle 2 | May, 01 2012 01:11:20-0700 | May, 01 2012 01:14:20-0700 | 180 |
| Non-idle 2 | May, 01 2012 01:15:20-0700 | May, 01 2012 01:15:20-0700 | 0 |
答案 1 :(得分：1)
这适用于所有支持窗口的RDBMS。 http://www.sqlfiddle.com/#!1/320e4/1
时间提取因每个RDBMS而异
with a as
(
select *, (rpm between 800 and 900) as idle_state,
case when
(rpm between 800 and 900) =
(lag(rpm) over(order by timestamp) between 800 and 900) then 0
else
1
end as detect_leader
from tbl
)
,grp as
(
select *, sum(detect_leader) over(order by timeStamp) as state_group
from a
)
,rn as
(
select state_group, idle_state,
min(timeStamp) as startTime, max(timeStamp) as endTime,
extract(epoch from ( max(timeStamp) - min(timeStamp) ) ) as duration
from grp
group by state_group, idle_state
order by state_group
)
select
case when idle_state then 'Idle ' else 'Non-idle ' end
|| (row_number() over(order by state_group) + 1) / 2 as Period,
rn.startTime, rn.endTime, rn.duration
from rn;
输出：
| PERIOD | STARTTIME | ENDTIME | DURATION |
|------------|----------------------------|----------------------------|----------|
| Idle 1 | May, 01 2012 01:02:56-0700 | May, 01 2012 01:05:55-0700 | 179 |
| Non-idle 1 | May, 01 2012 01:07:00-0700 | May, 01 2012 01:10:15-0700 | 195 |
| Idle 2 | May, 01 2012 01:11:20-0700 | May, 01 2012 01:14:20-0700 | 180 |
| Non-idle 2 | May, 01 2012 01:15:20-0700 | May, 01 2012 01:15:20-0700 | 0 |
请在此处查看查询进度：http://www.sqlfiddle.com/#!1/320e4/1