SPARQL：变量必须包含在Group By子句中

Question

对于每个sosa：featurefintest（房间），从该房间的相关传感器中获得最低温度。有100个房间。每个房间都有3个传感器。时间表是一年。

目标：查询以从传感器组中选择每房间最低温度加上温度发生的时间的时间。

示例数据（N3）：

prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix sosa: <http://www.w3.org/ns/sosa/> 
prefix xsd: <http://www.w3.org/2001/XMLSchema#> 
prefix ex: <http://www.example.com/> 

# Room FOIs
ex:room1Foi a sosa:FeatureOfInterest .
# ...
ex:room100Foi a sosa:FeatureOfInterest .

# Room 1 sensor observations 1/1/2021
ex:obs1Room1 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room1Foi ;
    sosa:resultTime "2021-01-01T00:00:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "51.4"^^xsd:decimal .
ex:obs2Room1 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room1Foi .
    sosa:resultTime "2021-01-01T08:00:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "50.2"^^xsd:decimal .
ex:obs3Room1 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room1Foi .
    sosa:resultTime "2021-01-01T:16:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "49.8"^^xsd:decimal .

# Room 1 sensor observations 1/2/2021
ex:obs4Room1 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room1Foi ;
    sosa:resultTime "2021-01-02T00:00:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "61.4"^^xsd:decimal .
ex:obs5Room1 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room1Foi .
    sosa:resultTime "2021-01-02T08:00:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "60.2"^^xsd:decimal .
ex:obs6Room1 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room1Foi .
    sosa:resultTime "2021-01-02T:16:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "59.8"^^xsd:decimal .

# ...

# Room 100 sensor observations 1/1/2021
ex:obs1Room100 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room100Foi ;
    sosa:resultTime "2021-01-01T00:00:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "50.7"^^xsd:decimal .
ex:obs2Room100 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room100Foi .
    sosa:resultTime "2021-01-01T08:00:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "51.6"^^xsd:decimal .
ex:obs3Room100 a sosa:Observation .
    sosa:hasFeatureOfInterest ex:room100Foi .
    sosa:resultTime "2021-01-01T:16:00"^^xsd:dateTime ;
    sosa:observedProperty "TEMP"^^xsd:string ;
    sosa:hasSimpleResult "48.0"^^xsd:decimal .

# Room 1 sensor observations 1/2/2021

# ...

一次尝试：

prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix sosa: <http://www.w3.org/ns/sosa/> 
prefix xsd: <http://www.w3.org/2001/XMLSchema#> 
prefix ex: <http://www.example1.com/> 
select ?oFoi ?day min(?val) as ?minTemp ?time where {
 {select ?f where {
  ?f a sosa:FeatureOfInterest .
 }}
 ?o a sosa:Observation ;
  sosa:hasFeatureOfInterest ?oFoi ;
  sosa:resultTime ?time ;
  sosa:observedProperty ?p ;
  sosa:hasSimpleResult ?val .
 filter(?oFoi = ?f) .
 bind(day(?t) as ?day) .
} group by ?oFoi ?day ?time
order by desc(?oFoi) asc(?day)

结果：

OFOI	Day	Mintemp	Time
http：//www.example.com/room1foi	1	51.4	2021-01-01-01 0:00:00:
00 。	​	​	​
​	​	​	​00
http://www.example.com/room1foi	2	59.8	2021-01-02 16:00:00:00
http://www.example.com/roome.com/room1foi	2	60.2 60.2	<代码> 2021-01-02 8:00:00
http://www.example.com/room1foi	2	61.4	2021-01-01-02 0:00:00
	。	​	​

​从子句中删除time将返回正确的行。但是，时间必须包括在内。

理想结果：

Ofoi	Day	Mintemp	Time
http://www.example.com/room1foi	1	49.8	2021-01-01-01 16:00:00
http://www.example.com/room/room/room1foi	2	59.89.898	2021-01-02 16:00:00
...	...	...

更新： 当同一天两次的温度相同（包括两个结果）时，这越来越近，但仍在包含多个结果：

select ?o2 ?oFoi2 ?day2 ?val2 sample(?t2) as ?tx2 ?p2 where {
  ?o2 a sosa:Observation ;
    sosa:hasFeatureOfInterest ?oFoi2 ;
    sosa:resultTime ?t2 ;
    sosa:observedProperty ?p2 ;
    sosa:hasSimpleResult ?val2 .
  bind(day(?t2) as ?day2) .  
  filter(?oFoi2 = ?oFoi) .
  filter(?day2 = ?day) . 
  filter(?val2 = ?vx) . 

  {select ?oFoi ?day min(?val) as ?vx where {
      {select ?f where {
        ?f a sosa:FeatureOfInterest .
      }}
      ?o a sosa:Observation ;
        sosa:hasFeatureOfInterest ?oFoi ;
        sosa:resultTime ?t ;
        sosa:observedProperty ?p ;
        sosa:hasSimpleResult ?val .
      filter(?oFoi = ?f) .
      bind(day(?t) as ?day) .
    } group by ?oFoi ?day 
    order by desc(?oFoi) asc(?day)
  }

} group by ?o2 ?oFoi2 ?day2 ?p2 ?val2

结果：

O2	OFOI2	Day2	val2 val2	tx2	p2
http://www.example3.com/obs3room100	http://www.example3.com/room100foi	1	48	2021-01-01-01-01 16:00:00:00:00:00 <	“ temp” ^^ http://www.w.w.w3.org/2001/xmlschema#字符串
http://www.example3.com/obs6room1	http://www.example3.com/ ROOM1FOI	2	59.8	2021-01-02 16:00:00	“ temp” ^^ http://www.w3.org/2001/xmlschema#string
http://www.example3.com/obs33333room1	http://www.example3.com/room1foi	1	-9.8	2021-01-01-01 16:00:00:00 < /code>	“ atemp” ^^ http://www.www.w.w.w.33.org/2001/xmlschema#字符串
http://www.example3.com/obs33room1	http://www.example3.com/ ROOM1FOI	1	-9.8	2021-01-01 7:59:00	“ atemp” ^^ http://www.w3.org/2001/xmlschema#string
... ...	... ... ...	... ... ...	...	... ...	org/2001/ xmlschema ..

糟糕：？o2是不必要的，并从上面的查询中将其删除为正确的解决方案。

Answer 1

添加外部选择似乎可以解决此问题。在时间上使用聚合，例如min（），max（），avg（），sample（）等都是汇总时间变量的有效方法。 理解

以帮助

select ?oFoi2 ?day2 ?val2 sample(?t2) as ?tx2 ?p2 where {
  ?o2 a sosa:Observation ;
    sosa:hasFeatureOfInterest ?oFoi2 ;
    sosa:resultTime ?t2 ;
    sosa:observedProperty ?p2 ;
    sosa:hasSimpleResult ?val2 .
  bind(day(?t2) as ?day2) .  
  filter(?oFoi2 = ?oFoi) .
  filter(?day2 = ?day) . 
  filter(?val2 = ?vx) . 

  {select ?oFoi ?day min(?val) as ?vx where {
      {select ?f where {
        ?f a sosa:FeatureOfInterest .
      }}
      ?o a sosa:Observation ;
        sosa:hasFeatureOfInterest ?oFoi ;
        sosa:resultTime ?t ;
        sosa:observedProperty ?p ;
        sosa:hasSimpleResult ?val .
      filter(?oFoi = ?f) .
      bind(day(?t) as ?day) .
    } group by ?oFoi ?day 
    order by desc(?oFoi) asc(?day)
  }

} group by ?oFoi2 ?day2 ?p2 ?val2

（

属性	atemp	的	。	添加
额外 “> http://www.example3.com/room100foi	1	48	2021-01-01 16:00:00:00	“ temp” ^^ http://www.w.33.org/2001/xmlschema#string
http://www.example3.com/room1foi	2	59.8	2021-01-01-02 16:00:00:	00 ^ http://wwwww.w.w.3.org/2001/xmlschemaunding
href =“ http://www.example3.com/room1foi” rel =“ nofollow noreferrer”> http://www.example3.com/room1foi	1	-9.8	2021-01-01-01 7： 59:00	“ atemp” ^^ http：// http://www.w3.org/ 2001/xmlschema＃string
...	... ...	...	...	...