求2个查询，谢谢~

Walkline 2018-12-26 05:46:11

表里字段包括温度和时间戳，我需要查询现在时间8小时以内的记录，8小时里每个小时取第一条和第六条记录，一共取16条记录，但是当前时间这个小时内可能没有这么多记录，那么只取第一条就行

第二个查询是这样，取8小时内温度有变化的记录，比如第一条记录23度，第二条记录23度，第三条记录23.1度，第四条记录24度，那么返回数据集应该是第一条、第三条、第四条记录，因为第一条作为起始点需要保留

求大佬们解决一下，谢谢~~

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Walkline 2018-12-30

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引用 2 楼吉普赛的歌的回复:

drop table if exists t;

create table t(

	id int not null AUTO_INCREMENT primary key,

	wd DECIMAL(10,2),

	addTime datetime

);

INSERT t (wd,addTime) values(10,'2018-12-27 03:00');

INSERT t (wd,addTime) values(10,'2018-12-27 03:01');

INSERT t (wd,addTime) values(11,'2018-12-27 03:10');

INSERT t (wd,addTime) values(12,'2018-12-27 03:12');

INSERT t (wd,addTime) values(13,'2018-12-27 03:13');

INSERT t (wd,addTime) values(14,'2018-12-27 03:20');

INSERT t (wd,addTime) values(10,'2018-12-27 04:00');

INSERT t (wd,addTime) values(10,'2018-12-27 05:01');

INSERT t (wd,addTime) values(11,'2018-12-27 06:10');

INSERT t (wd,addTime) values(12,'2018-12-27 07:12');

INSERT t (wd,addTime) values(13,'2018-12-27 08:13');

INSERT t (wd,addTime) values(23,'2018-12-27 09:20');

# 以上为测试数据



/*

1. 查询现在时间8小时以内的记录，8小时里每个小时取第一条和第六条记录，一共取16条记录，但是当前时间这个小时内可能没有这么多记录，那么只取第一条就行

*/

select * from (

select 

(

  SELECT COUNT(*) FROM t t2 WHERE 

  1=1

   AND DATE_FORMAT(t1.addTime,'%Y-%m-%d %H')= DATE_FORMAT(t2.addTime,'%Y-%m-%d %H') 

  AND t1.id >= t2.id

) as rid

,id

,wd

,addTime

from t as t1 where t1.addTime>DATE_ADD(t1.addTime,INTERVAL -8 hour)

) as tt

where rid in (1,6);

/*

+-----+----+-------+---------------------+

| rid | id | wd    | addTime             |

+-----+----+-------+---------------------+

|   1 |  1 | 10.00 | 2018-12-27 03:00:00 |

|   6 |  6 | 14.00 | 2018-12-27 03:20:00 |

|   1 |  7 | 10.00 | 2018-12-27 04:00:00 |

|   1 |  8 | 10.00 | 2018-12-27 05:01:00 |

|   1 |  9 | 11.00 | 2018-12-27 06:10:00 |

|   1 | 10 | 12.00 | 2018-12-27 07:12:00 |

|   1 | 11 | 13.00 | 2018-12-27 08:13:00 |

|   1 | 12 | 23.00 | 2018-12-27 09:20:00 |

+-----+----+-------+---------------------+

*/



/*

2. 取8小时内温度有变化的记录，比如第一条记录23度，第二条记录23度，第三条记录23.1度，第四条记录24度，那么返回数据集应该是第一条、第三条、第四条记录，因为第一条作为起始点需要保留

*/

drop TEMPORARY TABLE if exists tmp;

drop TEMPORARY TABLE if exists tmp2;

CREATE TEMPORARY  TABLE tmp(

	rid int,

	id int,

	wd DECIMAL(10,2),

	addTime datetime,

	timeSeg int

);

CREATE TEMPORARY  TABLE tmp2(

	rid int,

	id int,

	wd DECIMAL(10,2),

	addTime datetime,

	timeSeg int

);



insert into tmp

select * from (

select 

(

  SELECT COUNT(*) FROM t t2 WHERE 

  1=1

  AND DATE_FORMAT(t1.addTime,'%Y-%m-%d %H')= DATE_FORMAT(t2.addTime,'%Y-%m-%d %H') 

  AND t1.id >= t2.id

) as rid

,id

,wd

,addTime

,DATE_FORMAT(t1.addTime,'%Y%m%d%H') as timeSeg

from t as t1 where t1.addTime>DATE_ADD(t1.addTime,INTERVAL -8 hour)

) as tt

;

insert into tmp2

select * from tmp;



select 

id

,wd

,addTime

from (

select a.*,case when a.rid=1 or (b.wd is not null and a.wd!=b.wd) then 1 else 0 end as r from tmp as a 

    left join tmp2 as b on a.timeSeg=b.timeSeg and a.rid=b.rid+1

) as tt

where tt.r=1

order by tt.timeSeg,tt.rid

;

/*

+----+-------+---------------------+

| id | wd    | addTime             |

+----+-------+---------------------+

|  1 | 10.00 | 2018-12-27 03:00:00 |

|  3 | 11.00 | 2018-12-27 03:10:00 |

|  4 | 12.00 | 2018-12-27 03:12:00 |

|  5 | 13.00 | 2018-12-27 03:13:00 |

|  6 | 14.00 | 2018-12-27 03:20:00 |

|  7 | 10.00 | 2018-12-27 04:00:00 |

|  8 | 10.00 | 2018-12-27 05:01:00 |

|  9 | 11.00 | 2018-12-27 06:10:00 |

| 10 | 12.00 | 2018-12-27 07:12:00 |

| 11 | 13.00 | 2018-12-27 08:13:00 |

| 12 | 23.00 | 2018-12-27 09:20:00 |

+----+-------+---------------------+

*/

谢。。。。谢谢了，我还是用代码过滤一下吧。。。。。

吉普赛的歌 2018-12-27

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drop table if exists t;
create table t(
	id int not null AUTO_INCREMENT primary key,
	wd DECIMAL(10,2),
	addTime datetime
);
INSERT t (wd,addTime) values(10,'2018-12-27 03:00');
INSERT t (wd,addTime) values(10,'2018-12-27 03:01');
INSERT t (wd,addTime) values(11,'2018-12-27 03:10');
INSERT t (wd,addTime) values(12,'2018-12-27 03:12');
INSERT t (wd,addTime) values(13,'2018-12-27 03:13');
INSERT t (wd,addTime) values(14,'2018-12-27 03:20');
INSERT t (wd,addTime) values(10,'2018-12-27 04:00');
INSERT t (wd,addTime) values(10,'2018-12-27 05:01');
INSERT t (wd,addTime) values(11,'2018-12-27 06:10');
INSERT t (wd,addTime) values(12,'2018-12-27 07:12');
INSERT t (wd,addTime) values(13,'2018-12-27 08:13');
INSERT t (wd,addTime) values(23,'2018-12-27 09:20');
# 以上为测试数据

/*
1. 查询现在时间8小时以内的记录，8小时里每个小时取第一条和第六条记录，一共取16条记录，但是当前时间这个小时内可能没有这么多记录，那么只取第一条就行
*/
select * from (
select 
(
  SELECT COUNT(*) FROM t t2 WHERE 
  1=1
   AND DATE_FORMAT(t1.addTime,'%Y-%m-%d %H')= DATE_FORMAT(t2.addTime,'%Y-%m-%d %H') 
  AND t1.id >= t2.id
) as rid
,id
,wd
,addTime
from t as t1 where t1.addTime>DATE_ADD(t1.addTime,INTERVAL -8 hour)
) as tt
where rid in (1,6);
/*
+-----+----+-------+---------------------+
| rid | id | wd    | addTime             |
+-----+----+-------+---------------------+
|   1 |  1 | 10.00 | 2018-12-27 03:00:00 |
|   6 |  6 | 14.00 | 2018-12-27 03:20:00 |
|   1 |  7 | 10.00 | 2018-12-27 04:00:00 |
|   1 |  8 | 10.00 | 2018-12-27 05:01:00 |
|   1 |  9 | 11.00 | 2018-12-27 06:10:00 |
|   1 | 10 | 12.00 | 2018-12-27 07:12:00 |
|   1 | 11 | 13.00 | 2018-12-27 08:13:00 |
|   1 | 12 | 23.00 | 2018-12-27 09:20:00 |
+-----+----+-------+---------------------+
*/

/*
2. 取8小时内温度有变化的记录，比如第一条记录23度，第二条记录23度，第三条记录23.1度，第四条记录24度，那么返回数据集应该是第一条、第三条、第四条记录，因为第一条作为起始点需要保留
*/
drop TEMPORARY TABLE if exists tmp;
drop TEMPORARY TABLE if exists tmp2;
CREATE TEMPORARY  TABLE tmp(
	rid int,
	id int,
	wd DECIMAL(10,2),
	addTime datetime,
	timeSeg int
);
CREATE TEMPORARY  TABLE tmp2(
	rid int,
	id int,
	wd DECIMAL(10,2),
	addTime datetime,
	timeSeg int
);

insert into tmp
select * from (
select 
(
  SELECT COUNT(*) FROM t t2 WHERE 
  1=1
  AND DATE_FORMAT(t1.addTime,'%Y-%m-%d %H')= DATE_FORMAT(t2.addTime,'%Y-%m-%d %H') 
  AND t1.id >= t2.id
) as rid
,id
,wd
,addTime
,DATE_FORMAT(t1.addTime,'%Y%m%d%H') as timeSeg
from t as t1 where t1.addTime>DATE_ADD(t1.addTime,INTERVAL -8 hour)
) as tt
;
insert into tmp2
select * from tmp;

select 
id
,wd
,addTime
from (
select a.*,case when a.rid=1 or (b.wd is not null and a.wd!=b.wd) then 1 else 0 end as r from tmp as a 
    left join tmp2 as b on a.timeSeg=b.timeSeg and a.rid=b.rid+1
) as tt
where tt.r=1
order by tt.timeSeg,tt.rid
;
/*
+----+-------+---------------------+
| id | wd    | addTime             |
+----+-------+---------------------+
|  1 | 10.00 | 2018-12-27 03:00:00 |
|  3 | 11.00 | 2018-12-27 03:10:00 |
|  4 | 12.00 | 2018-12-27 03:12:00 |
|  5 | 13.00 | 2018-12-27 03:13:00 |
|  6 | 14.00 | 2018-12-27 03:20:00 |
|  7 | 10.00 | 2018-12-27 04:00:00 |
|  8 | 10.00 | 2018-12-27 05:01:00 |
|  9 | 11.00 | 2018-12-27 06:10:00 |
| 10 | 12.00 | 2018-12-27 07:12:00 |
| 11 | 13.00 | 2018-12-27 08:13:00 |
| 12 | 23.00 | 2018-12-27 09:20:00 |
+----+-------+---------------------+
*/

吉普赛的歌 2018-12-27

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drop table if exists t;
create table t(
	id int not null AUTO_INCREMENT primary key,
	wd DECIMAL(10,2),
	addTime datetime
);
INSERT t (wd,addTime) values(10,'2018-12-27 03:00');
INSERT t (wd,addTime) values(10,'2018-12-27 03:01');
INSERT t (wd,addTime) values(11,'2018-12-27 03:10');
INSERT t (wd,addTime) values(12,'2018-12-27 03:12');
INSERT t (wd,addTime) values(13,'2018-12-27 03:13');
INSERT t (wd,addTime) values(14,'2018-12-27 03:20');
INSERT t (wd,addTime) values(10,'2018-12-27 04:00');
INSERT t (wd,addTime) values(10,'2018-12-27 05:01');
INSERT t (wd,addTime) values(11,'2018-12-27 06:10');
INSERT t (wd,addTime) values(12,'2018-12-27 07:12');
INSERT t (wd,addTime) values(13,'2018-12-27 08:13');
INSERT t (wd,addTime) values(23,'2018-12-27 09:20');
# 以上为测试数据

/*
1. 查询现在时间8小时以内的记录，8小时里每个小时取第一条和第六条记录，一共取16条记录，但是当前时间这个小时内可能没有这么多记录，那么只取第一条就行
*/
select * from (
select 
(
  SELECT COUNT(*) FROM t t2 WHERE 
  1=1
   AND DATE_FORMAT(t1.addTime,'%Y-%m-%d %H')= DATE_FORMAT(t2.addTime,'%Y-%m-%d %H') 
  AND t1.id >= t2.id
) as rid
,id
,wd
,addTime
from t as t1 where t1.addTime>DATE_ADD(t1.addTime,INTERVAL -8 hour)
) as tt
where rid in (1,6);
/*
+-----+----+-------+---------------------+
| rid | id | wd    | addTime             |
+-----+----+-------+---------------------+
|   1 |  1 | 10.00 | 2018-12-27 03:00:00 |
|   6 |  6 | 14.00 | 2018-12-27 03:20:00 |
|   1 |  7 | 10.00 | 2018-12-27 04:00:00 |
|   1 |  8 | 10.00 | 2018-12-27 05:01:00 |
|   1 |  9 | 11.00 | 2018-12-27 06:10:00 |
|   1 | 10 | 12.00 | 2018-12-27 07:12:00 |
|   1 | 11 | 13.00 | 2018-12-27 08:13:00 |
|   1 | 12 | 23.00 | 2018-12-27 09:20:00 |
+-----+----+-------+---------------------+
*/