【Elasticsearch】全文检索 组合检索
全文检索
- 1.全文检索
- 1.1 准备测试数据
- 1.2 案例分析
- 1.2.1 match(分词检索)
- 1.2.2 match_phrase(短语检索)
- 1.2.3 match_phrase_prefix(短语前缀匹配)
- 1.2.4 multi_match(多字段匹配)
- 1.2.5 query_string(高级查询语法)
- 1.2.6 simple_query_string
- 1.3 对比总结表
- 2.组合检索
1.全文检索
1.1 准备测试数据
创建一个索引。
PUT /products
{"mappings": {"properties": {"name": {"type": "text", "fields": {"keyword": {"type": "keyword"}}},"price": {"type": "double"},"category": {"type": "keyword"},"tags": {"type": "keyword"},"description": {"type": "text"},"stock": {"type": "integer"},"sku": {"type": "keyword"},"created_at": {"type": "date"},"metadata": {"type": "object"}}}
}
插入测试数据。
POST /products/_bulk
{"index":{}}
{"name":"Laptop X1","price":1299.99,"category":"electronics","tags":["new","sale"],"description":"High performance laptop","stock":50,"sku":"LP-X1-2023","created_at":"2023-01-15","metadata":{"weight":1.5,"color":"silver"}}
{"index":{}}
{"name":"Smartphone S10","price":899.99,"category":"electronics","tags":["new","popular"],"description":"Latest smartphone model","stock":120,"sku":"SP-S10-2023","created_at":"2023-02-20","metadata":{"weight":0.3,"color":"black"}}
{"index":{}}
{"name":"Wireless Headphones","price":199.99,"category":"audio","tags":["sale","popular"],"description":"Noise cancelling headphones","stock":75,"sku":"WH-200-2022","created_at":"2022-11-10","metadata":{"weight":0.25,"color":"white"}}
{"index":{}}
{"name":"Smart Watch","price":249.99,"category":"wearables","tags":["new","featured"],"description":"Fitness tracking smartwatch","stock":30,"sku":"SW-500-2023","created_at":"2023-03-05","metadata":{"weight":0.1,"color":"black"}}
{"index":{}}
{"name":"4K TV","price":1499.99,"category":"electronics","tags":["premium","large"],"description":"55-inch 4K television","stock":15,"sku":"TV-4K-55-2023","created_at":"2023-01-25","metadata":{"weight":18.5,"color":"black"}}
{"index":{}}
{"name":"Bluetooth Speaker","price":129.99,"category":"audio","tags":["portable"],"description":"Waterproof bluetooth speaker","stock":60,"sku":"BS-100-2022","created_at":"2022-12-15","metadata":{"weight":0.8,"color":"blue"}}
{"index":{}}
{"name":"Gaming Mouse","price":79.99,"category":"accessories","tags":["gaming"],"description":"High DPI gaming mouse","stock":90,"sku":"GM-X200","created_at":"2023-02-01","metadata":{"weight":0.12,"color":"rgb"}}
{"index":{}}
{"name":"External SSD 1TB","price":159.99,"category":"storage","tags":["fast","reliable"],"description":"Portable SSD drive","stock":45,"sku":"ESSD-1TB-2023","created_at":"2023-03-10","metadata":{"weight":0.05,"color":"gray"}}
{"index":{}}
{"name":"Keyboard Pro","price":109.99,"category":"accessories","tags":["ergonomic"],"description":"Mechanical keyboard","stock":25,"sku":"KB-PRO-2023","created_at":"2023-03-15","metadata":{"weight":1.1,"color":"black"}}
{"index":{}}
{"name":"Tablet T8","price":499.99,"category":"electronics","tags":["new","portable"],"description":"10-inch tablet","stock":40,"sku":"TAB-T8-2023","created_at":"2023-02-28","metadata":{"weight":0.5,"color":"silver"}}
{"index":{}}
{"name":"Camera DSLR","price":899.99,"category":"photography","tags":["professional"],"description":"24MP DSLR camera","stock":20,"sku":"CAM-DSLR-24","created_at":"2023-01-10","metadata":{"weight":0.7,"color":"black"}}
{"index":{}}
{"name":"Monitor 27\"","price":299.99,"category":"electronics","tags":["office"],"description":"27-inch office monitor","stock":35,"sku":"MON-27-2023","created_at":"2023-02-15","metadata":{"weight":4.2,"color":"black"}}
1.2 案例分析
1.2.1 match(分词检索)
对字段进行分词后匹配,支持模糊匹配和运算符。
GET /products/_search
{"query": {"match": {"description": {"query": "niose cancelling", // 故意拼错 "noise" 测试模糊匹配"fuzziness": "AUTO"}}}
}
1.2.2 match_phrase(短语检索)
要求词语按顺序完整出现,可设置 slop
,允许中间有其他词。
GET /products/_search
{"query": {"match_phrase": {"description": {"query": "high laptop","slop": 1 // 允许中间有 1 个其他词}}}
}
1.2.3 match_phrase_prefix(短语前缀匹配)
短语匹配,但最后一个词支持前缀匹配。
GET /products/_search
{"query": {"match_phrase_prefix": {"name": {"query": "Smart Wa", // 匹配 "Smart Watch" 等"max_expansions": 10 // 限制扩展数量}}}
}
1.2.4 multi_match(多字段匹配)
multi_match
检索适用于在多个字段上执行 match
检索的场景。它提供了一种方便的方法来在多个字段中间同时搜索指定的关键词,从而实现跨字段的高效检索。通过使用 multi_match
检索,用户可以简化复杂的多字段查询,优化搜索体验,并确保结果满足各种检索需求。
GET /products/_search
{"query": {"multi_match": {"query": "portable","fields": ["name", "description", "tags"],"type": "best_fields"}}
}
由于涉及的字段不止一个,multi_match
检索在处理结果评分时采用特殊的评分机制,包括 most_fields
、best_fields
、cross_fields
等评分方式。这些评分方式确定了如何对每个字段获取的分数进行整合。
为了强调 tags
字段在搜索结果中的重要性,我们使用 ^3
来提高其权重。这意味着匹配 tags
字段的文档具有更高的相关性分数。
GET /products/_search
{"query": {"multi_match": {"query": "portable","fields": ["name", "description", "tags^3"], "type": "best_fields"}}
}
1.2.5 query_string(高级查询语法)
支持 Lucene 查询语法,功能强大但较复杂。
例如:查找在 name
或 description
字段中包含 laptop
或 smartphone
,并且 price
字段值在 100 100 100 到 1000 1000 1000 之间的所有产品文档。
GET /products/_search
{"query": {"query_string": {"query": "(laptop OR smartphone) AND price:[100 TO 1000]","fields": ["name", "description"],"default_operator": "AND"}}
}
1.2.6 simple_query_string
更简单的语法,对用户输入更友好,容错性更好。
例如,搜索同时满足以下条件的产品:
- 仅在商品名称(
name
)和描述(description
)字段中搜索。 - 必须包含
speaker
(由+speaker
表示)。 - 必须不包含
blue
(由-blue
表示)。 - 最好包含
waterproof
(没有前缀符号,作为可选条件)。
GET /products/_search
{"query": {"simple_query_string": {"query": "waterproof +speaker -blue", "fields": ["name", "description"],"default_operator": "AND"}}
}
+
必须包含,-
必须不包含。"default_operator": "AND"
表示当有多个搜索词时(没有+
/-
前缀的词),默认使用AND
逻辑。AND
操作符:提高精确度(结果更少但更相关)。OR
操作符:提高召回率(结果更多但可能包含不相关项)。
如果用 SQL 表示,类似于:
SELECT * FROM products
WHERE (name LIKE '%speaker%' OR description LIKE '%speaker%')
AND (name NOT LIKE '%blue%' AND description NOT LIKE '%blue%')
AND (name LIKE '%waterproof%' OR description LIKE '%waterproof%')
注意:虽然 metadata.color
包含 blue
,但没有检查 metadata.color
的内容,所以会按照上述内容返回。
如果真正目的是排除蓝色产品,应该这样查询:
GET /products/_search
{"query": {"bool": {"must": {"simple_query_string": {"query": "waterproof +speaker","fields": ["name", "description"]}},"must_not": {"term": {"metadata.color": "blue"}}}}
}
1.3 对比总结表
查询类型 | 特点 | 适用场景 | 语法复杂度 |
---|---|---|---|
match | 基本分词匹配,支持模糊 | 常规搜索 | 低 |
match_phrase | 精确短语匹配 | 引号搜索、固定短语 | 低 |
match_phrase_prefix | 短语+最后词前缀 | 自动补全 | 中 |
multi_match | 多字段搜索 | 跨字段搜索 | 中 |
query_string | 完整查询语法 | 高级搜索界面 | 高 |
simple_query_string | 简化语法 | 用户直接输入 | 中 |
2.组合检索
must
:查询结果必须满足指定条件。must_not
:查询结果必须不满足指定条件。在此情况下,召回的数据评分为 0 0 0,且不考虑评分。filter
:过滤条件,同样不考虑评分,召回的数据评分为 0 0 0。使用filter
可以借助缓存机制提高查询性能。should
:查询结果可以满足的部分条件,具体满足条件的最小数量由minimum_should_match
参数控制。
🚀 Elasticsearch 查询语句中的
query
和filter
具有不同的用途。
query
用于评估文档相关性,并对结果进行评分,通常用于搜索场景。filter
用于筛选文档,不会对文档评分,通常用于过滤场景。
业务要求:查找符合以下条件的相关产品,其中:
- 必须在
category
或description
中包含electronics
。 - 优先显示以下产品:
description
中提到high performance
的产品。- 被标记为
popular
的产品。 - 同时满足多个加分条件的产品会排名更靠前。
GET /products/_search
{"query": {"bool": {"must": [{"multi_match": {"query": "electronics","fields": ["category^2", "description"],"type": "most_fields"}}],"should": [{"match_phrase": {"description": {"query": "high performance","slop": 2}}},{"match": {"tags": {"query": "popular"}}}],"minimum_should_match": 1}}
}