ElasticSearch - Return Unique Values

Question

How would I get the values of all the languages from the records and make them unique.

Records

PUT items/1
{ "language" : 10 }

PUT items/2
{ "language" : 11 }

PUT items/3
{ "language" : 10 }

Query

GET items/_search
{ ... }

# => Expected Response
[10, 11]

Any help would be great.

Answer 1

You can use the terms aggregation.

{
"size": 0,
"aggs" : {
    "langs" : {
        "terms" : { "field" : "language",  "size" : 500 }
    }
}}

The size parameter within the aggregation specifies the maximum number of terms to include in the aggregation result. If you need all results, set this to a value that is larger than the number of unique terms in your data.

A search will return something like:

{
"took" : 16,
"timed_out" : false,
"_shards" : {
  "total" : 2,
  "successful" : 2,
  "failed" : 0
},
"hits" : {
"total" : 1000000,
"max_score" : 0.0,
"hits" : [ ]
},
"aggregations" : {
  "langs" : {
    "buckets" : [ {
      "key" : "10",
      "doc_count" : 244812
    }, {
      "key" : "11",
      "doc_count" : 136794
 
    }, {
      "key" : "12",
      "doc_count" : 32312
       } ]
    }
  }
}