Elasticsearch Query DSL备忘（1）（Constant score query和Bool Query）

Query DSL (Domain Specific Language)，基于json的查询方式

1、Constant score query，常量分值查询，目的就是返回指定的score，一般都结合filter使用，因为filter context忽略score。

GET /customer/_search
{
  "query": {
    "constant_score": {
      "filter": {
        "match": {
          "addr": "天津，北京"
        }
      },
      "boost": 5.2
    }
  }
}

result:返回结果中score都是被指定的5.2
{
  "took" : 8,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 2,
    "max_score" : 5.2,
    "hits" : [
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "510221197801023611",
        "_score" : 5.2,
        "_source" : {
          "name" : "王刚",
          "id" : "510221197801023611",
          "addr" : "北京市朝阳区未名路109号",
          "tel" : "13901004491"
        }
      },
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "51228199001013611",
        "_score" : 5.2,
        "_source" : {
          "name" : "白开心",
          "id" : "51228199001013611",
          "addr" : "天津市海港路1021号",
          "tel" : "13590850990"
        }
      }
    ]
  }
}

2、bool query，布尔查询

Bool查询对应Lucene中的BooleanQuery，它由一个或者多个子句组成，每个子句都有特定的类型。

• must  返回的文档必须满足must子句的条件，并且参与计算分值
• filter  返回的文档必须满足filter子句的条件。但是不会像must一样参与计算分值
• should 返回的文档可能满足should子句的条件。bool查询在query context中，并且有一个must或filter子句，即使没有一个should查询匹配，文档也会进行bool匹配。在这种情况下，这些should仅用于影响分数。如果在filter context中，或者没有must或filter子句，那么should子句必须和文档匹配，才能匹配bool查询。这种行为由minimum_should_match 参与决定。
• must_not 返回的文档必须不满足must_not定义的条件。

官网的例子：

POST _search
{
  "query": {
    "bool" : {
      "must" : {
        "term" : { "user" : "kimchy" }
      },
      "filter": {
        "term" : { "tag" : "tech" }
      },
      "must_not" : {
        "range" : {
          "age" : { "gte" : 10, "lte" : 20 }
        }
      },
      "should" : [
        { "term" : { "tag" : "wow" } },
        { "term" : { "tag" : "elasticsearch" } }
      ],
      "minimum_should_match" : 1,
      "boost" : 1.0
    }
  }
}

bool查询案例分解：

第一步：查询name为“李云龙”的文档

GET /customer/_search
{
  "query": {
    "bool": {
      "must": {
        "term":{"name.keyword":"李云龙"}
      }
    }
  }
}
返回三个文档：
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 3,
    "max_score" : 1.4916549,
    "hits" : [
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "4",
        "_score" : 1.4916549,
        "_source" : {
          "name" : "李云龙",
          "id" : "510221197001013611",
          "addr" : "昆明市滇池路阳光时代1栋1单元",
          "tel" : "13808712808"
        }
      },
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "224",
        "_score" : 1.4916549,
        "_source" : {
          "name" : "李云龙",
          "id" : "224",
          "addr" : "天津市阳光路2008号",
          "tel" : "13908712808"
        }
      },
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "510221197001013611",
        "_score" : 1.4916549,
        "_source" : {
          "name" : "李云龙",
          "id" : "510221197001013611",
          "addr" : "上海市浦东区华北路8号",
          "tel" : "13908712808"
        }
      }
    ]
  }
}

第二步：加入过滤条件，只保留id为510221197001013611的文档

GET /customer/_search
{
  "query": {
    "bool": {
      "must": {
        "term":{"name.keyword":"李云龙"}
      },
      "filter": {
        "term": {
          "id": "510221197001013611"
        }
      }
    }
  }
}

返回结果减少到2个文档，并且score相同：
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 2,
    "max_score" : 1.4916549,
    "hits" : [
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "4",
        "_score" : 1.4916549,
        "_source" : {
          "name" : "李云龙",
          "id" : "510221197001013611",
          "addr" : "昆明市滇池路阳光时代1栋1单元",
          "tel" : "13808712808"
        }
      },
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "510221197001013611",
        "_score" : 1.4916549,
        "_source" : {
          "name" : "李云龙",
          "id" : "510221197001013611",
          "addr" : "上海市浦东区华北路8号",
          "tel" : "13908712808"
        }
      }
    ]
  }
}

第三步：使用should，判断addr中必须有昆明市，这种情况下should子句会影响计分

GET /customer/_search
{
  "query": {
    "bool": {
      "must": {
        "term":{"name.keyword":"李云龙"}
      },
      "filter": {
        "term": {
          "id": "510221197001013611"
        }
      },
      "should": [
        {"match": {
          "addr": "昆明市"
        }}
      ]
    }
  }
}
返回结果中，地址是昆明市的文档score加重
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 2,
    "max_score" : 3.408528,
    "hits" : [
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "4",
        "_score" : 3.408528,
        "_source" : {
          "name" : "李云龙",
          "id" : "510221197001013611",
          "addr" : "昆明市滇池路阳光时代1栋1单元",
          "tel" : "13808712808"
        }
      },
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "510221197001013611",
        "_score" : 1.5720221,
        "_source" : {
          "name" : "李云龙",
          "id" : "510221197001013611",
          "addr" : "上海市浦东区华北路8号",
          "tel" : "13908712808"
        }
      }
    ]
  }
}

第四步：加入must_not排除上海

GET /customer/_search
{
  "query": {
    "bool": {
      "must": {
        "term":{"name.keyword":"李云龙"}
      },
      "filter": {
        "term": {
          "id": "510221197001013611"
        }
      },
      "should": [
        {"match": {
          "addr": "昆明市"
        }}
      ],
      "must_not": [
        {"match": {
          "addr": "上海"
        }}
      ]
    }
  }
}

只返回一个文档：
{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 1,
    "max_score" : 3.408528,
    "hits" : [
      {
        "_index" : "customer",
        "_type" : "doc",
        "_id" : "4",
        "_score" : 3.408528,
        "_source" : {
          "name" : "李云龙",
          "id" : "510221197001013611",
          "addr" : "昆明市滇池路阳光时代1栋1单元",
          "tel" : "13808712808"
        }
      }
    ]
  }
}