How can I get element at a particular index in elasticsearch? - elasticsearch

Question

I have stored three json objects in elasticsearch, each object has a title and projects array.
{"name": "haris","projects": [{"title": "Splunk"},{"title": "QRadar"},{"title": "LogAnalysis"}]}
{"name": "khalid","projects": [{"title": "MS"},{"title": "Google"},{"title": "Apple"}]}
{"name": "Hamid","projects": [{"title": "Toyota"},{"title": "Honda"},{"title": "Kia"}]}
I have written a query to extract a particular object by _id and its specific property projects
curl -XGET 'localhost:9200/jsontest/_search?pretty' -d '{"query" : { "match" : {"_id":"AV1kzzZqAzHWQ2S7B8f1"} }, "_source": ["projects"]}'
As expected it returns projects object
{
"took" : 3,
"timed_out" : false,
"_shards" : {
"total" : 5,
"successful" : 5,
"failed" : 0
},
"hits" : {
"total" : 1,
"max_score" : 1.0,
"hits" : [
{
"_index" : "jsontest",
"_type" : "json",
"_id" : "AV1kzzZqAzHWQ2S7B8f1",
"_score" : 1.0,
"_source" : {
"projects" : [{"title" : "Splunk"},{"title" : "QRadar"},{"title" : "LogAnalysis"}
]
}
}
]
}
}
Question: is there a way to retrieve value at a particular index of projects? This is dummy data, in my real scenario projects can have a large number of elements and each element itself is a json object with a lot of properties. I only need to retrieve value at certain index of projects.

Answer 1

Here is what i would do.
First the mapping
PUT test/my_objects/_mapping
{
"properties": {
"name":{
"type": "string",
"index": "not_analyzed"
},
"projects": {
"type": "nested"
}
}
}
Second Projects are indexed
PUT test/my_objects/1111
{
"name": "haris",
"projects": [
{"title": "Splunk"},
{"title": "QRadar"},
{"title": "LogAnalysis"}
]
}
Finally the aggregation query
GET test/my_objects/_search
{
"aggs": {
"by_name": {
"terms": {
"field": "name"
},
"aggs": {
"by_project": {
"nested": {
"path": "projects"
},
"aggs": {
"by_title": {
"terms": {
"field": "projects.title"
}
}
}
}
}
}
}
}
its not tested and a bit tedious because of the nested aggs but should work if you manipulate it further for you requirements