Can any one tell me to make aggregation on dynamic field_name or restructure data

[tushar.sharma.cse (Tushar Sharma)]

{"updated_on":"2020-11-15","journal":{"2020-10-20":"a","2020-10-21":"b"}}
{"updated_on":"2020-11-14","journal":{"2020-10-21":"c","2020-10-23":"b"}}
 
 
How to form aggregation query based on “journal”  hash key’s(where key’s e.g. “2020-10-20” is dynamic ) .If not possible then how to structure data to generate below output
 
 
Result should be:
{ "aggregations" : {
    "journal_status_counts" : {
      "buckets" : [
{
          "key_as_string" : "2020-10-20",
          "key" : 1603305000000,
          "doc_count" : 2
},
  {        "key_as_string" : "2020-10-21",
          "key" : 1603305000000,
          "doc_count" : 1
},
  {  "key_as_string" : "2020-10-22",
          "key" : 1603305000000,
          "doc_count" : 0
}
,
  {  "key_as_string" : "2020-10-23",
          "key" : 1603305000000,
          "doc_count" : 1
}
,
  {  "key_as_string" : "2020-10-24",
          "key" : 1603305000000,
          "doc_count" : 0
}
…
]
…
}
}
}

[wangqinghuan (Wang)]

@tushar.sharma.cse

{"updated_on":"2020-11-15","journal":{"2020-10-20":"a","2020-10-21":"b"}}

Could you make some change?
{"updated_on":"2020-11-15","journal":[{"date":"2020-10-20","value":"a"},{"date":"2020-10-21","values":"b"}]}

[tushar.sharma.cse (Tushar Sharma)]

Thanks Wang But I have resolved this by key as value and value as key
{"updated_on":"2020-11-15","journal":{"a":"2020-10-20","b":"2020-10-21"}}