example.sh

curl -XPUT "http://localhost:9200/index2" -d'
{
    "mappings": {
        "child" : {
            "_parent": {
               "type": "child"
            }
        }
    }
}'

curl -XPUT "http://localhost:9200/index2/parent/1" -d'
{
    "field" : "value"
}'

curl -XPUT "http://localhost:9200/index2/child/1?parent=1" -d'
{
    "field" : "value"
}'

curl -XPUT "http://localhost:9200/index2/parent/2" -d'
{
    "field" : "value"
}'

curl -XPUT "http://localhost:9200/index2/child/2?parent=2" -d'
{
    "field" : "value"
}'

curl -XPUT "http://localhost:9200/index2/child/3?parent=2" -d'
{
    "field" : "value"
}'

# Only return parent 2, since the minimum of required of 2 child match.
curl -XPOST "http://localhost:9200/index2/_search" -d'
{
    "query": {
        "has_child": {
            "type": "child",
            "query": {
                "constant_score": {
                   "query": {
                       "match": {
                          "field": "value"
                       }
                   }
                }
            },
            "score_type": "sum"
        }
    },
    "min_score" : 2
}'