Elasticsearch系列(二)

Elasticsearch系列(二)

本文基于ES6.4版本，我也是出于学习阶段，对学习内容做个记录，如果文中有错误，请指出。

实验数据：

index：book

type：novel

mappings：

{"mappings": {"novel": {"dynamic": "false","properties": {"word_count": {"type": "integer"},"author": {"type": "keyword"},"title": {"type": "text"},"publish_date": {"format": "yyyy-MM-dd HH:mm:ss||yyyy-MM-dd||epoch_millis","type": "date"}}}}
}

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通过put创建索引，使用head可视化界面，数据如下：

Elasticsearch的查询分为：

1、子条件查询：查询特定字段的特定值

Query context

查询过程中，除了判断Document是否满足条件，还会计算出_score表示匹配程度，数值越大，证明匹配程度越高

1、查询全部：/book/novel/_search

"hits": {"total": 10,"max_score": 1.0,"hits": [{"_index": "book","_type": "novel","_id": "5","_score": 1.0,"_source": {"title": "永夜君王","word_count": "110000","publish_date": "2015-03-01","author": "烟雨江南"}},{"_index": "book","_type": "novel","_id": "8","_score": 1.0,"_source": {"title": "万古令","word_count": "110000","publish_date": "2015-03-01","author": "听奕"}},{"_index": "book","_type": "novel","_id": "9","_score": 1.0,"_source": {"title": "天帝传","word_count": "110000","publish_date": "2015-03-01","author": "飞天鱼"}},{"_index": "book","_type": "novel","_id": "10","_score": 1.0,"_source": {"title": "剑来","word_count": "110000","publish_date": "2015-03-01","author": "烽火戏诸侯"}},{"_index": "book","_type": "novel","_id": "2","_score": 1.0,"_source": {"title": "完美世界","word_count": "130000","publish_date": "2017-03-01","author": "辰东"}},{"_index": "book","_type": "novel","_id": "4","_score": 1.0,"_source": {"title": "民国谍影","word_count": "110000","publish_date": "2019-03-01","author": "寻青藤"}},{"_index": "book","_type": "novel","_id": "6","_score": 1.0,"_source": {"title": "遮天","word_count": "110000","publish_date": "2015-03-01","author": "辰东"}},{"_index": "book","_type": "novel","_id": "1","_score": 1.0,"_source": {"title": "万古神帝","word_count": "30000","publish_date": "2017-01-01","author": "飞天鱼"}},{"_index": "book","_type": "novel","_id": "7","_score": 1.0,"_source": {"title": "圣墟","word_count": "110000","publish_date": "2015-03-01","author": "辰东"}},{"_index": "book","_type": "novel","_id": "3","_score": 1.0,"_source": {"title": "星辰变","word_count": "100000","publish_date": "2018-03-01","author": "我吃西红柿"}}]}

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2、查询id为1的数据：/book/novel/1

{"_index": "book","_type": "novel","_id": "1","_version": 1,"found": true,"_source": {"title": "万古神帝","word_count": "30000","publish_date": "2017-01-01","author": "飞天鱼"}
}

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3、只查询title和author字段：/1?_source=title,author

{"_index": "book","_type": "novel","_id": "1","_version": 1,"found": true,"_source": {"author": "飞天鱼","title": "万古神帝"}
}

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4、只是显示_source部分：/book/novel/1/_source

{"title": "万古神帝","word_count": "30000","publish_date": "2017-01-01","author": "飞天鱼"
}

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5、筛选单字段查询：/book/novel/_search

{"query": {"match": {"author": "飞天鱼"}}
}

"hits": {"total": 2,"max_score": 1.2039728,"hits": [{"_index": "book","_type": "novel","_id": "9","_score": 1.2039728,"_source": {"title": "天帝传","word_count": "110000","publish_date": "2015-03-01","author": "飞天鱼"}},{"_index": "book","_type": "novel","_id": "1","_score": 0.6931472,"_source": {"title": "万古神帝","word_count": "30000","publish_date": "2017-01-01","author": "飞天鱼"}}]}

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6、limit：我们查询到2条数据，如果我们只想得到第一条数据，可以使用from和size联合查询

{"query": {"match": {"author": "飞天鱼"}},"from": 0,"size": 1
}

"hits": {"total": 2,"max_score": 1.2039728,"hits": [{"_index": "book","_type": "novel","_id": "9","_score": 1.2039728,"_source": {"title": "天帝传","word_count": "110000","publish_date": "2015-03-01","author": "飞天鱼"}}]}

View Code al=2，但是只返回了第一条数据，from为从第几条开始，size我返回的条数 7、order by： 这里选择对word_count字段进行倒叙排序

{"query": {"match": {"author": "辰东"}},"sort": [{"word_count": {"order": "desc"}}    ]
}

"hits": {"total": 3,"max_score": null,"hits": [{"_index": "book","_type": "novel","_id": "2","_score": null,"_source": {"title": "完美世界","word_count": "130000","publish_date": "2017-03-01","author": "辰东"},"sort": [130000]},{"_index": "book","_type": "novel","_id": "6","_score": null,"_source": {"title": "遮天","word_count": "110000","publish_date": "2015-03-01","author": "辰东"},"sort": [110000]},{"_index": "book","_type": "novel","_id": "7","_score": null,"_source": {"title": "圣墟","word_count": "110000","publish_date": "2015-03-01","author": "辰东"},"sort": [110000]}]}

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8、其余匹配match_phrase：

query、match的方式本质上就是模糊查询，而且中文会自动分词到最大粒度，可以看到会查询到只要匹配任意一个字都是可以的

{"query": {"match": {"title": "万古神帝"}}
}

"hits": {"total": 3,"max_score": 2.439878,"hits": [{"_index": "book","_type": "novel","_id": "1","_score": 2.439878,"_source": {"title": "万古神帝","word_count": "30000","publish_date": "2017-01-01","author": "飞天鱼"}},{"_index": "book","_type": "novel","_id": "8","_score": 2.4079456,"_source": {"title": "万古令","word_count": "110000","publish_date": "2015-03-01","author": "听奕"}},{"_index": "book","_type": "novel","_id": "9","_score": 1.2039728,"_source": {"title": "天帝传","word_count": "110000","publish_date": "2015-03-01","author": "飞天鱼"}}]}

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所以这里有了其余匹配match_phrase，结果只有完全包含"万古神帝"的title才可以被查询到

{"query": {"match_phrase": {"title": "万古神帝"}}
}

"hits": {"total": 1,"max_score": 2.439878,"hits": [{"_index": "book","_type": "novel","_id": "1","_score": 2.439878,"_source": {"title": "万古神帝","word_count": "30000","publish_date": "2017-01-01","author": "飞天鱼"}}]}

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9、多条件查询multi_match：查询title或者author包含"万古神帝"的数据

{"query": {"multi_match": {"query": "万古神天","fields": ["title","author"]}}
}

"hits": {"total": 4,"max_score": 2.4079456,"hits": [{"_index": "book","_type": "novel","_id": "8","_score": 2.4079456,"_source": {"title": "万古令","word_count": "110000","publish_date": "2015-03-01","author": "听奕"}},{"_index": "book","_type": "novel","_id": "1","_score": 1.8299085,"_source": {"title": "万古神帝","word_count": "30000","publish_date": "2017-01-01","author": "飞天鱼"}},{"_index": "book","_type": "novel","_id": "9","_score": 1.2039728,"_source": {"title": "天帝传","word_count": "110000","publish_date": "2015-03-01","author": "飞天鱼"}},{"_index": "book","_type": "novel","_id": "6","_score": 1.1727304,"_source": {"title": "遮天","word_count": "110000","publish_date": "2015-03-01","author": "辰东"}}]}

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10、语法查询query_string：

{"query": {"query_string": {"query": "万古"}}
}

这里和match没有区别，query可以使用AND和OR，match的filed也可以，注意这里一定是大写，小写就被当做搜索的内容了

{"query": {"query_string": {"query": "万古 OR 剑来"}}
}

{"query": {"match": {"title": "万古 OR 剑来"}}
}

指定fields：

{"query": {"query_string": {"query": "万古 OR 剑来 OR 辰东 ","fields": ["author","title"]}}
}

11、精确匹配term：

title为text类型，author为keyword类型，实验发现查询title只有是单个字的时候才能匹配(精确匹配查不到数据)，而author必须是精确匹配

例如：title不支持精确匹配，支持模糊查询(而且是单个字才可以，多个字照样查不到数据)

{"query": {"term": {"title": "剑来"}}
}

如果只是查询一个字就可以

{"query": {"term": {"title": "来"}}
}

"hits": {"total": 1,"max_score": 1.3940737,"hits": [{"_index": "book","_type": "novel","_id": "10","_score": 1.3940737,"_source": {"title": "剑来","word_count": "110000","publish_date": "2015-03-01","author": "烽火戏诸侯"}}]}

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查询author字段：有三条数据

{"query": {"term": {"author": "辰东"}}
}

"hits": [{"_index": "book","_type": "novel","_id": "7","_score": 0.6931472,"_source": {"title": "圣墟","word_count": "110000","publish_date": "2015-03-01","author": "辰东"}},{"_index": "book","_type": "novel","_id": "2","_score": 0.47000363,"_source": {"title": "完美世界","word_count": "130000","publish_date": "2017-03-01","author": "辰东"}},{"_index": "book","_type": "novel","_id": "6","_score": 0.47000363,"_source": {"title": "遮天","word_count": "110000","publish_date": "2015-03-01","author": "辰东"}}]}

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author不知道模糊查询：下面结果为null

{"query": {"term": {"author": "东"}}
}

12、范围查找range：包括integer和日期类型，日期支持now函数，也就是当前日期

{"query": {"range": {"word_count": {"gt": 110000,"lte": 130000}}}
}

"hits": {"total": 1,"max_score": 1.0,"hits": [{"_index": "book","_type": "novel","_id": "2","_score": 1.0,"_source": {"title": "完美世界","word_count": "130000","publish_date": "2017-03-01","author": "辰东"}}]}

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Filter context

查询过程中，只是判断Document是否满足条件，只有yes or no。用来做数据过滤，而且ES还会对结果进行缓存，效率相对query更高一点

{"query": {"bool": {"filter": {"term": {"word_count": 130000}}}}
}

"hits": {"total": 1,"max_score": 0.0,"hits": [{"_index": "book","_type": "novel","_id": "2","_score": 0.0,"_source": {"title": "完美世界","word_count": "130000","publish_date": "2017-03-01","author": "辰东"}}]}

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2、复合条件查询：组合子条件查询

1、固定分数查询：不支持match，支持filter

{"query": {"constant_score": {"filter": {"match": {"title": "天帝传"}}}}
}{"query": {"constant_score": {"filter": {"match": {"title": "天帝传"}},"boost": 2}}
}

2、bool查询：

should：就是or的关系

{"query": {"bool": {"should": [{"match": {"author": "辰东"}},{"match": {"title": "天帝传"}}]}}
}

must：相当于and

{"query": {"bool": {"must": [{"match": {"author": "辰东"}},{"match": {"title": "天帝传"}}]}}
}

must_not：相当于<>

{"query": {"bool": {"must_not": {"term": {"author": "辰东"}}}}
}

bool查询也可以使用filter：

{"query": {"bool": {"must": [{"match": {"author": "辰东"}},{"match": {"title": "天帝传"}}],"filter": [{"term": {"word_count": 110000}}    ]}}
}

 aggregations：

{"aggs": {"group_by_author": {"terms": {"field": "author"}}}
}

"aggregations": {"group_by_author": {"doc_count_error_upper_bound": 0,"sum_other_doc_count": 0,"buckets": [{"key": "辰东","doc_count": 3},{"key": "飞天鱼","doc_count": 2},{"key": "听奕","doc_count": 1},{"key": "寻青藤","doc_count": 1},{"key": "我吃西红柿","doc_count": 1},{"key": "烟雨江南","doc_count": 1},{"key": "烽火戏诸侯","doc_count": 1}]}}

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支持多聚合结果：

{"aggs": {"group_by_author": {"terms": {"field": "author"}},"group_by_word_count": {"terms": {"field": "word_count"}}}
}

aggregations除了支持term，还有stats、min、max、avg等

{"aggs": {"group_by_author": {"stats": {"field": "word_count"}}}
}

"aggregations": {"group_by_author": {"count": 10,"min": 30000.0,"max": 130000.0,"avg": 103000.0,"sum": 1030000.0}}

avg：

{"aggs": {"group_by_author": {"avg": {"field": "word_count"}}}
}

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