Search service should support _exists_ query for nested attributes

I want to search data against some kind in which certain attribute should exist and the same attribute value should not be null. I am able to formulate a search query and it works as expected for flat attribute directly present inside "data" block of a record as shown below.

search query example for flat data attribute

{ "kind": "osdu:wks:master-data--Well:1.0.0", "query": "_exists_:data.InitialOperatorID AND NOT data.InitialOperatorID.keyword:null", "limit": 1000, "sort": { "field": [ "version" ], "order": [ "DESC" ] }, "returnedFields": [ "id", "version", "data.GeoContexts.FieldID", "data.InitialOperatorID" ] }

However, when I tried similar query for attribute inside nested object, then it does not work.

search query example for nested data attribute

{ "kind": "osdu:wks:master-data--Wellbore:1.0.0", "query": "NOT nested(data.GeoContexts, (FieldID.keyword:null)) AND _exists_:nested(data.GeoContexts, (FieldID))", "limit": 1000, "sort": { "field": [ "version" ], "order": [ "DESC" ] }, "returnedFields": [ "id", "version", "data.GeoContexts.FieldID" ] }

Proposed solution: Search service should support exists query for nested attributes as well.