how to merge two aggregation results in elasticsearch - elasticsearch-5

Question

I am facing issues with elasticsearch aggregation grouping inside top_hits. or i need unique students count in the tophits
Elastic search mapping:
{
"board" : {
"properties" : {
"notApplied" : {
"type" : "date"
}
}
}
}
Query :
{
"size": 0,
"query": {},
"aggs": {
"notApplied": {
"filter": {
"exists": {
"field": "board.notApplied"
}
},
"aggs": {
"top_student_hits": {
"top_hits": {
"sort": [
{
"board.notApplied": {
"order": "desc"
}
}
],
"script_fields": {
"dues": {
"script": {
"source": "if (doc.containsKey('board.notApplied') && doc['board.notApplied'].size() != 0) { (doc['board.notApplied'].value.toInstant().toEpochMilli()-params.date)/86400000 } else { 0; }",
"params": {
"date": 1669939199059 // --> < 1 day
}
}
}
},
"_source": {
"includes": [
"id",
"studentName",
"usercode",
"board.notApplied",
"userId"
]
},
"size": 5
}
}
}
}
}
}
Output for the above query :
{
"took" : 11,
...
"aggregations" : {
"notApplied" : {
"doc_count" : 42,
"top_student_hits" : {
"hits" : {
"total" : {
"value" : 42,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "applications",
"_type" : "_doc",
"_id" : "4b85533822f91e9b99392f16dedaae1f",
"_score" : null,
"_source" : {
"board" : {
"notApplied" : "2022-10-25T00:00:00.000Z"
},
"studentName" : "Joe",
"id" : "4b85533822f91e9b99392f16dedaae1f",
"userId" : "45a47d1314041ab287a277679ff19922"
},
"fields" : {
"dues" : [
-37
]
},
"sort" : [
1666656000000
]
},
{
"_index" : "applications",
"_type" : "_doc",
"_id" : "1897f32d2d7f691e42c3fe6ebe631c7d",
"_score" : null,
"_source" : {
"board" : {
"notApplied" : "2022-10-25T00:00:00.000Z"
},
"studentName" : "Joe",
"id" : "1897f32d2d7f691e42c3fe6ebe631c7d",
"userId" : "45a47d1314041ab287a277679ff19922"
},
"fields" : {
"dues" : [
-37
]
},
"sort" : [
1666656000000
]
},
{
"_index" : "applications",
"_type" : "_doc",
"_id" : "f0b25dc9a911782ace5af36db7bfbc1f",
"_score" : null,
"_source" : {
"board" : {
"notApplied" : "2022-10-25T00:00:00.000Z"
},
"studentName" : "Sam",
"id" : "f0b25dc9a911782ace5af36db7bfbc1f",
"userId" : "d84f9e5231daa902c37921de9126cad7"
},
"fields" : {
"dues" : [
-37
]
},
"sort" : [
1666656000000
]
},
{
"_index" : "applications",
"_type" : "_doc",
"_id" : "e7f84fa978a553e77716ab479d3d6ce5",
"_score" : null,
"_source" : {
"board" : {
"notApplied" : "2022-10-13T00:00:00.000Z"
},
"id" : "e7f84fa978a553e77716ab479d3d6ce5",
"studentName" : "Sam",
"userId" : "d84f9e5231daa902c37921de9126cad7"
},
"fields" : {
"dues" : [
-49
]
},
"sort" : [
1665619200000
]
},
{
"_index" : "applications",
"_type" : "_doc",
"_id" : "9cba9f6b0d7a28ef739b321291d00170",
"_score" : null,
"_source" : {
"board" : {
"notApplied" : "2022-09-20T00:00:00.000Z"
},
"studentName" : "Ctest17 ",
"id" : "9cba9f6b0d7a28ef739b321291d00170",
"userId" : "ddaf6d6162c8317fd90fec0b870132ce"
},
"fields" : {
"dues" : [
-72
]
},
"sort" : [
1663632000000
]
}
]
}
}
}
}
}
I am getting the exact results but it has been duplicated by userId.
i need a result in top_hits without duplicates or the buckets should be grouped by userId. also the result should be sort desc by (dues or notApplied) field.
can any one help me to resolve this?