十八、Elasticsearch 教程： 查询描述语言

Elasticsearch 使用基于 JSON 数据格式的查询来执行搜索

查询由两个子句组成:

1、 叶子查询短语；

这种短语包括 **匹配** ( matching ) 、词 ( term ) 或范围 ( range )，用于在特定的字段中查找特定的值

2、 复合查询短语；

这种查询短语由 **叶子查询短语** 和其它复合查询短语组成，用于提取所需要的数据

Elasticsearch 支持数量庞大的各种不同类型的查询

这些查询以 query 开始，然后使用 JSON 对象包含条件和过滤器

本章接下来的内容将学习和介绍各种不同类型的查询

匹配所有的查询

这是最基本的查询，它会返回所有的内容，其中的每个对象的得分都是 1.0

这种查询的请求正文一般为

{
   "query":{
      "match_all":{}
   }

例如下面的请求用于查询 user* 索引中的所有数据

POST http://localhost:9200/user*/_search?pretty

请求正文

{
   "query":{
      "match_all":{}
   }

响应内容

{
    "took": 21,
    "timed_out": false,
    "_shards": {
        "total": 10,
        "successful": 10,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": 5,
        "max_score": 1,
        "hits": [
            {
                "_index": "user",
                "_type": "user",
                "_id": "2",
                "_score": 1,
                "_source": {
                    "nickname": "枫晚",
                    "description": "停车坐爰枫林晚",
                    "street": "苏州大学",
                    "city": "Suzhou",
                    "state": "Jiangsu",
                    "zip": "215006",
                    "location": [
                        120.65426,
                        31.30797
                    ],
                    "money": 10235,
                    "tags": [
                        "Java",
                        "Android"
                    ],
                    "vitality": "3.5"
                }
            },
            {
                "_index": "user_admin",
                "_type": "user",
                "_id": "2",
                "_score": 1,
                "_source": {
                    "nickname": "雅少",
                    "description": "虚怀若谷",
                    "street": "四川大学",
                    "city": "Chengdu",
                    "state": "Sichuan",
                    "zip": "610044",
                    "location": [
                        104.094537,
                        30.640174
                    ],
                    "money": 68023,
                    "tags": [
                        "Python",
                        "HTML"
                    ],
                    "vitality": "7.8"
                }
            },
            {
                "_index": "user",
                "_type": "user",
                "_id": "1",
                "_score": 1,
                "_source": {
                    "nickname": "question",
                    "description": "问题少年也是少年",
                    "street": "张江高科技园区",
                    "city": "Shanghai",
                    "state": "Shanghai",
                    "zip": "201204",
                    "location": [
                        121.60632,
                        31.199305
                    ],
                    "money": 13648,
                    "tags": [
                        "VUE",
                        "HTML"
                    ],
                    "vitality": "8.8"
                }
            },
            {
                "_index": "user_admin",
                "_type": "user",
                "_id": "1",
                "_score": 1,
                "_source": {
                    "nickname": "站长",
                    "description": "pottercoding.cn 程序员波特，程序员编程资料站 ，教程 ",
                    "street": "东四十条",
                    "city": "Beijing",
                    "state": "Beijing",
                    "zip": "100007",
                    "location": [
                        116.432727,
                        39.937732
                    ],
                    "money": 5201814,
                    "tags": [
                        "PHP",
                        "Python"
                    ],
                    "vitality": "9.0"
                }
            },
            {
                "_index": "user_admin",
                "_type": "user",
                "_id": "3",
                "_score": 1,
                "_source": {
                    "nickname": "歌者",
                    "description": "程序设计也是设计，研发新菜也是研发",
                    "street": "五道口",
                    "city": "Beijing",
                    "state": "Beijing",
                    "zip": "100083",
                    "location": [
                        116.346346,
                        39.999333
                    ],
                    "money": 71128,
                    "tags": [
                        "Java",
                        "Scala"
                    ],
                    "vitality": "6.9"
                }
            }
        ]
    }