In ElasticSearch, how do I filter the nested documents in my result?

user_7453 0
Viewed 16624

Suppose, in ElasticSearch 5, I have data with nesting like:

{"number":1234, "names": [ 
  {"firstName": "John", "lastName": "Smith"}, 
  {"firstName": "Al", "lastName": "Jones"}
]},  
...

And I want to query for hits with number 1234 but return only the names that match "lastName": "Jones", so that my result omits names that don't match. In other words, I want to get back only part of the matching document, based on a term query or similar.

A simple nested query won't do, as such would be filtering top-level results. Any ideas?

{ "query" : { "bool": { "filter":[
    { "term": { "number":1234} },
    ????  something with "lastName": "Jones" ????
] } } }

I want back: 

hits: [
   {"number":1234, "names": [ 
     {"firstName": "Al", "lastName": "Jones"}
   ]},  
   ...
]
elasticsearch
3 Answers

Similar but a bit different, use the should parameter and then look at inner hits for the names. This will return the top level doc and then inner_hits will have any hits.

   { 
      "_source": {
        "excludes": ["names"]
      },
       "query":{
          "bool":{
             "must":[
                {
                   "term":{
                      "number":{
                         "value":"1234"
                      }
                   }
                }
             ],
             should: [
             {
                "nested":{
                   "path":"names",
                   "query":{
                      "term":{
                         "names.lastName":"Jones"
                      }
                   },
                   "inner_hits":{
                   }
                }
             }

             ]
          }
       }
    }
user_46478020
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