Displays how to use aggregations in Elasticsearch on documents with nested types

StackOverflow Question: Aggs on Nested Documents

# Answer for: http://stackoverflow.com/questions/24631409/average-and-histogram-aggregation-on-nested-fields-in-elasticsearch

curl -XPUT "http://localhost:9200/aggs/test/_mapping" -d'
{
   "test": {
      "properties": {
         "doctxt": {
            "type": "string"
         },
         "nested": {
            "type": "nested",
            "properties": {
               "pos": {
                  "type": "long"
               },
               "txt": {
                  "type": "string"
               }
            }
         }
      }
   }
}'

curl -XPOST "http://localhost:9200/aggs/test/1" -d'
{
   "doctxt": "doca",
   "nested": [
      {
         "pos": 1,
         "txt": "terma"
      },
      {
         "pos": 2,
         "txt": "termb"
      },
      {
         "pos": 3,
         "txt": "termc"
      }
   ]
}'

curl -XPOST "http://localhost:9200/aggs/test/2" -d'
{
   "doctxt": "docb",
   "nested": [
      {
         "pos": 1,
         "txt": "termd"
      },
      {
         "pos": 2,
         "txt": "terma"
      },
      {
         "pos": 3,
         "txt": "termb"
      }
   ]
}'

curl -XGET "http://localhost:9200/aggs/test/_search" -d'
{
   "query": {
      "match_all": {}
   },
   "aggs": {
      "count": {
         "nested": {
            "path": "nested"
         },
         "aggs": {
            "terms": {
               "terms": {
                  "field": "nested.txt"
               },
               "aggs": {
                  "avg_pos": {
                     "avg": {
                        "field": "nested.pos"
                     }
                  }
               }
            }
         }
      }
   }
}'