Querying array with nested objects in Elasticsearch to get multiple objects - elasticsearch

Question

I have data in Elasticsearch in the below format -
"segments": [
{"id": "ABC", "value":123},
{"id": "PQR", "value":345},
{"id": "DEF", "value":567},
{"id": "XYZ", "value":789},
]
I want to retrieve all segments where id is "ABC" or "DEF".
I looked up the docs (https://www.elastic.co/guide/en/elasticsearch/reference/7.9/query-dsl-nested-query.html) and few examples on YouTube but the all look to retrieve only a single object while I want to retrieve more than 1.
Is there a way to do this?

Answer 1

You can use nested query with inner hits as shown here.
I hope your index mapping is looks like below and segments field is define as nested
"mappings": {
"properties": {
"segments": {
"type": "nested",
"properties": {
"id": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"value": {
"type": "long"
}
}
}
}
}
You can use below Query:
{
"_source" : false,
"query": {
"nested": {
"path": "segments",
"query": {
"terms": {
"segments.id.keyword": [
"ABC",
"DEF"
]
}
},
"inner_hits": {}
}
}
}
Response:
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 1,
"hits": [
{
"_index": "73895503",
"_id": "TmM8iYMBrWOLJcwdvQGG",
"_score": 1,
"inner_hits": {
"segments": {
"hits": {
"total": {
"value": 2,
"relation": "eq"
},
"max_score": 1,
"hits": [
{
"_index": "73895503",
"_id": "TmM8iYMBrWOLJcwdvQGG",
"_nested": {
"field": "segments",
"offset": 0
},
"_score": 1,
"_source": {
"id": "ABC",
"value": 123
}
},
{
"_index": "73895503",
"_id": "TmM8iYMBrWOLJcwdvQGG",
"_nested": {
"field": "segments",
"offset": 2
},
"_score": 1,
"_source": {
"id": "DEF",
"value": 567
}
}
]
}
}
}
}
]
}