Sum Aggregation

A single-value metrics aggregation that sums up numeric values that are extracted from the aggregated documents. These values can be extracted either from specific numeric fields in the documents, or be generated by a provided script.

Assuming the data consists of documents representing sales records we can sum the sale price of all hats with:

POST /sales/_search?size=0
{
    "query" : {
        "constant_score" : {
            "filter" : {
                "match" : { "type" : "hat" }
            }
        }
    },
    "aggs" : {
        "hat_prices" : { "sum" : { "field" : "price" } }
    }
}

Resulting in:

{
    ...
    "aggregations": {
        "hat_prices": {
           "value": 450.0
        }
    }
}

The name of the aggregation (intraday_return above) also serves as the key by which the aggregation result can be retrieved from the returned response.

Script

We could also use a script to fetch the sales price:

POST /sales/_search?size=0
{
    "query" : {
        "constant_score" : {
            "filter" : {
                "match" : { "type" : "hat" }
            }
        }
    },
    "aggs" : {
        "hat_prices" : {
            "sum" : {
                "script" : {
                   "source": "doc.price.value"
                }
            }
        }
    }
}

This will interpret the script parameter as an inline script with the painless script language and no script parameters. To use a stored script use the following syntax:

POST /sales/_search?size=0
{
    "query" : {
        "constant_score" : {
            "filter" : {
                "match" : { "type" : "hat" }
            }
        }
    },
    "aggs" : {
        "hat_prices" : {
            "sum" : {
                "script" : {
                    "id": "my_script",
                    "params" : {
                        "field" : "price"
                    }
                }
            }
        }
    }
}

Value Script

It is also possible to access the field value from the script using _value. For example, this will sum the square of the prices for all hats:

POST /sales/_search?size=0
{
    "query" : {
        "constant_score" : {
            "filter" : {
                "match" : { "type" : "hat" }
            }
        }
    },
    "aggs" : {
        "square_hats" : {
            "sum" : {
                "field" : "price",
                "script" : {
                    "source": "_value * _value"
                }
            }
        }
    }
}

Missing value

The missing parameter defines how documents that are missing a value should be treated. By default documents missing the value will be ignored but it is also possible to treat them as if they had a value. For example, this treats all hat sales without a price as being 100.

POST /sales/_search?size=0
{
    "query" : {
        "constant_score" : {
            "filter" : {
                "match" : { "type" : "hat" }
            }
        }
    },
    "aggs" : {
        "hat_prices" : {
            "sum" : {
                "field" : "price",
                "missing": 100 
            }
        }
    }
}