三、Elasticsearch 簡單數據分析

先將文本 field 的 fielddata 屬性設置爲 true

- Elasticsearch 5.x 版本寫法
PUT /ecommerce/_mapping/product

- Elasticsearch 7.x 版本寫法
PUT /ecommerce/_mapping/product?include_type_name=true
{
    "properties": {
        "tags": {
            "type": "text",
            "fielddata": true
        }
    }
}

注意: es 不同版本之間語法存在差異

計算每個商品tag下的商品數量(分組求和)

GET /ecommerce/product/_search
{
    "size": 0,
    "aggs": {
        "group_by_tags": {
            "terms": {
                "field": "tags"
            }
        }
    }
}

size 控制元數據返回的數目，0 則不返回元數據

對名稱中包含 yagao 的商品，計算每個 tag 下的商品數量

GET /ecommerce/product/_search
{
    "size": 0,
    "query": {
        "match": {
            "name": "yagao"
        }
    },
    "aggs": {
        "group_by_tags": {
            "terms": {
                "field": "tags"
            }
        }
    }
}

計算每個 tag 下的商品平均價格

GET /ecommerce/product/_search
{
    "size": 0,
    "aggs": {
        "group_by_tags": {
            "terms": {
                "field": "tags"
            },
            "aggs": {
                "avg_price": {
                    "avg": {
                        "field": "price"
                    }
                }
            }
        }
    }
}

計算每個 tag 下的商品平均價格,並將結果按照平均價格降序排序

GET /ecommerce/product/_search
{
    "size": 0,
    "aggs": {
        "group_by_tags": {
            "terms": {
                "field": "tags",
                "order": {
                    "avg_price": "asc"
                }
            },
            "aggs": {
                "avg_price": {
                    "avg": {
                        "field": "price"
                    }
                }
            }
        }
    }
}

按照指定的價格範圍區間進行分組，然後在每組內在按照tag進行分組，最後再計算每組的平均價格

GET /ecommerce/product/_search
{
    "size": 0,
    "aggs": {
        "group_by_price": {
            "range": {
                "field": "price",
                "ranges": [
                    {
                        "from": 0,
                        "to": 20
                    },
                    {
                        "from": 20,
                        "to": 40
                    },
                    {
                        "from": 40,
                        "to": 60
                    }
                ]
            },
            "aggs": {
                "group_by_tags": {
                    "terms": {
                        "field": "tags"
                    },
                    "aggs": {
                        "avg_price": {
                            "avg": {
                                "field": "price"
                            }
                        }
                    }
                }
            }
        }
    }
}