elasticsearch,计算两个字段的乘积。

Question

每成交一笔生成一条记录，其中有两个字段，一个是单价（price）,一个是成交量（amount），怎么计算出5天内成交总额？

Answer 1

curl -XPOST 'localhost:9200/order/_search?size=0&pretty' -H 'Content-Type: application/json' -d'
{
    "query" : {
        "filtered": {
            "query": {"match_all": {}},
                "filter": {
                    "range": {
                        "date": {
                            "from": ...,
                            "to": ...
                        }
                    }
                }
            }
        }
    },
    "aggs": {
        "total": {
            "scripted_metric": {
                "init_script" : "params._agg.transactions = []",
                "map_script" : "params._agg.transactions.add(doc.price.value * doc.amount.value)",
                "combine_script" : "double total = 0; for (t in params._agg.transactions) { total += t } return total",
                "reduce_script" : "double total = 0; for (a in params._aggs) { total += a } return total"
            }
        }
    }
}
'