ElasticSearch: Query nested array for empty and specific value in single query - elasticsearch

Question

Documents structure -
{
"hits": [
{
"_type": "_doc",
"_id": "ef0a2c44179a513476b080cc2a585d95",
"_source": {
"DIVISION_NUMBER": 44,
"MATCHES": [
{
"MATCH_STATUS": "APPROVED",
"UPDATED_ON": 1599171303000
}
]
}
},
{
"_type": "_doc",
"_id": "ef0a2c44179a513476b080cc2a585d95",
"_source": {
"DIVISION_NUMBER": 44,
"MATCHES": [ ]
}
}
]
}
Question - MATCHES is a nested array inside there is a text field MATCH_STATUS that can have any values say "APPROVED","REJECTED".
I am looking to search ALL documents that contain MATCH_STATUS having values say "APPROVED", "RECOMMENDED" as well as where there is no data in MATCHES (empty array "MATCHES": [ ]). Please note I want this in a single query.
I am able to do this in two separate queries like this -
GET all matches with status = RECOMMENDED, APPROVED
"must": [
{
"nested": {
"path": "MATCHES",
"query": {
"terms": {
"MATCHES.MATCH_STATUS.keyword": [
"APPROVED",
"RECOMMENDED"
]
}
}
}
}
]
GET all matches having empty array "MATCHES" : [ ]
{
"size": 5000,
"query": {
"bool": {
"filter": [],
"must_not": [
{
"nested": {
"path": "MATCHES",
"query": {
"exists": {
"field": "MATCHES"
}
}
}
}
]
}
},
"from": 0
}

Answer 1

You can combine both queries using should clause.
{
"query": {
"bool": {
"minimum_should_match": 1,
"should": [
{
"nested": {
"path": "MATCHES",
"query": {
"bool": {
"minimum_should_match": 1,
"should": [
{
"terms": {
"MATCHES.MATCH_STATUS.keyword": [
"APPROVED",
"RECOMMENDED"
]
}
}
]
}
}
}
},
{
"bool": {
"must_not": [
{
"nested": {
"path": "MATCHES",
"query": {
"bool": {
"filter": {
"exists": {
"field": "MATCHES"
}
}
}
}
}
}
]
}
}
]
}
}
}
Update: To answer your comment.
Missing aggregation does not support nested field for now. There is open issue as of now.
To get count of empty matches, you can use a filter aggregation with the nested query wrapped into the must_not clause of the bool query.
{
"aggs": {
"missing_matches_agg": {
"filter": {
"bool": {
"must_not": {
"nested": {
"query": {
"match_all": {}
},
"path": "MATCHES"
}
}
}
}
}
}
}