二、Elasticsearch 六種搜索方式

查詢結果解釋

• took - 耗費多少毫秒
• time_out - 是否超時
• _shards - 數據分片情況
• hits.total - 查詢結果的數量
• hits.max_score - document 對於一個 search 的相關度匹配分數，越相關分數越高
• hits.hits - 匹配 document 的詳細數據

query string search

• 語法

GET /index/type/_search

查詢全部商品

GET /ecommerce/product/_search
{
    "took": 0,
    "timed_out": false,
    "_shards": {
        "total": 1,
        "successful": 1,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": {
            "value": 3,
            "relation": "eq"
        },
        "max_score": 1,
        "hits": [
            {
                "_index": "ecommerce",
                "_type": "product",
                "_id": "1",
                "_score": 1,
                "_source": {
                    "name": "gaolujie yagao",
                    "desc": "gaoxiao meibai",
                    "price": 30,
                    "producer": "gaolujie producer",
                    "tags": [
                        "meibai",
                        "fangzhu"
                    ]
                }
            }
        ...
        ]
    }
}

條件查詢排序

查詢商品名稱中包含 yagao 的商品，而且按照售價降序排序

GET /ecommerce/product/_search?q=name:yagao&sort=price:desc

query DSL 【常用】

Domain Specified Language：特定領域的語言

• 語法

GET /index/type/_search
{
    "query": {
        "match_all": {}
    }
}

請求體放在 request body 裏面 ,可以用 json 格式來構建各種複雜的語法，比 query string search 強大

查詢所有商品

GET /ecommerce/product/_search
{
    "query": {
        "match_all": {}
    }
}

條件查詢排序

查詢商品名稱中包含 yagao 的商品，而且按照售價降序排序

GET /ecommerce/product/_search
{
    "query": {
        "match": {
            "name": "yagao"
        }
    },
    "sort": [
        {
            "price": "desc"
        }
    ]
}

分頁查詢

當前總共3條商品數據，假設每頁顯示1條，現在顯示第2頁，所以只查出來第2個商品

GET /ecommerce/product/_search
{
  "query":{
    "match_all": {}
  },
  "from": 1,
  "size": 1
}

查詢指定屬性

指定只查詢商品的 name、price 屬性

GET /ecommerce/product/_search
{
    "query": {
        "match_all": {}
    },
    "_source": [
        "name",
        "price"
    ]
}

query filter

範圍查詢

搜索商品名稱包含 yaogao ，而且售價大於 25 元的商品

GET /ecommerce/product/_search
{
    "query": {
        "bool": {
            "must": [
                {
                    "match": {
                        "name": "yagao"
                    }
                }
            ],
            "filter": {
                "range": {
                    "price": {
                        "gt": 25
                    }
                }
            }
        }
    }
}

• gt : 大於
• lt : 小於
• eq : 等於
• ne : 不等於
• gte : 大於等於
• lte : 小於等於

full-text search

全文檢索 - 會將輸入的關鍵字拆解，去倒排索引裏面一一匹配，只要匹配上任意一個拆解後的單詞，就可以作爲結果返回

• 先新增一條數據

PUT /ecommerce/product/4
{
    "name": "special yagao",
    "desc": "special meibai",
    "price": 50,
    "producer": "special yagao producer",
    "tag": [
        "meibai"
    ]
}

• 查詢 producer

GET /ecommerce/product/_search
{
  "query":{
    "match": {
      "producer":"yagao producer"
    }
  }
}

• 查詢結果展示

{
    "took": 2,
    "timed_out": false,
    "_shards": {
        "total": 1,
        "successful": 1,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": {
            "value": 4,
            "relation": "eq"
        },
        "max_score": 1.2825179,
        "hits": [
            {
                "_index": "ecommerce",
                "_type": "product",
                "_id": "4",
                "_score": 1.2825179,
                "_source": {
                    "name": "special yagao",
                    "desc": "special meibai",
                    "price": 50,
                    "producer": "special yagao producer",
                    "tag": [
                        "meibai"
                    ]
                }
            },
            {
                "_index": "ecommerce",
                "_type": "product",
                "_id": "3",
                "_score": 0.09037233,
                "_source": {
                    "name": "zhonghua yagao",
                    "desc": "caoben zhiwu",
                    "price": 40,
                    "producer": "zhonghua producer",
                    "tags": [
                        "qingxin",
                        "fangzhu"
                    ]
                }
            },
            {
                "_index": "ecommerce",
                "_type": "product",
                "_id": "2",
                "_score": 0.09037233,
                "_source": {
                    "name": "jiajieshi yagao",
                    "desc": "youxiao fangzhu",
                    "price": 25,
                    "producer": "jiajieshi producer",
                    "tags": [
                        "fangzhu"
                    ]
                }
            },
            {
                "_index": "ecommerce",
                "_type": "product",
                "_id": "1",
                "_score": 0.09037233,
                "_source": {
                    "name": "gaolujie yagao",
                    "desc": "gaoxiao meibai",
                    "price": 30,
                    "producer": "gaolujie producer",
                    "tags": [
                        "name"
                    ]
                }
            }
        ]
    }
}

當 yagao producer 作爲查詢條件時會被拆分成 yagao、producer 兩個查詢條件，但是查詢結果的 _score 會體現跟原始查詢條件的匹配度

phrase search

短語搜索 - 跟全文檢索相反，搜索關鍵字必須在指定的字段文本中完全匹配

GET /ecommerce/product/_search
{
    "query": {
        "match_phrase": {
            "producer": "yagao producer"
        }
    }
}

highlight search

高亮搜索 - 被匹配的關鍵字將會在查詢結果中高亮標註（默認<em>）

GET /ecommerce/product/_search
{
    "query": {
        "match": {
            "producer": "producer"
        }
    },
    "highlight": {
        "fields": {
            "producer": {}
        }
    }
}