I am new to Elastic Search and was exploring aggregation query. The documents I have are in the format -
{"name":"A",
"class":"10th",
"subjects":{
"S1":92,
"S2":92,
"S3":92,
}
}
another document can be -
{"name":"B",
"class":"10th",
"subjects":{
"S3":92,
"S2":92,
"S5":92,
}
}
We have about 40k such documents in our ES with the Subjects varying from student to student. The query to the system can be to aggregate all subject-wise scores for a given class. We tried to create a bucket aggregation query as explained in this guide here, however, this generates a single bucket per document and in our understanding requires an explicit mention of every subject.
We want to system to generate subject wise aggregate for the data by executing a single aggregation query, the problem I face is that in our data the subjects could vary from student to student and we don't have a global list of subject keys.
We wrote the following script but this only works if we know all possible subjects.
GET student_data_v1_1/_search
{ "query" :
{"match" :
{ "class" : "' + query + '" }},
"aggs" : { "my_buckets" : { "terms" :
{ "field" : "subjects", "size":10000 },
"aggregations": {"the_avg":
{"avg": { "field": "subjects.value" }}} }},
"size" : 0 }'
but this query only works for the document structure, but does not work multiple subjects are defined where we may not know the key-pair -
{"name":"A",
"class":"10th",
"subjects":{
"value":93
}
}
An alternate form the document is present is that the subject is a list of dictionaries -
{"name":"A",
"class":"10th",
"subjects":[
{"S1":92},
{"S2":92},
{"S3":92},
]
}
Having an aggregation query to solve either of the 2 document formats would be helpful.