一，数据结构

"properties": {"type": { "type": "keyword" } ,"title": { "type": "text", "analyzer": "ik_smart" }, "long_title": { "type": "text", "analyzer": "ik_smart" }, "category_id": { "type": "integer" },"category": { "type": "keyword" },"category_path": { "type": "keyword" },"description": { "type": "text", "analyzer": "ik_smart" },"price": { "type": "scaled_float", "scaling_factor": 100 },"on_sale": { "type": "boolean" },"rating": { "type": "float" },"sold_count": { "type": "integer" },"review_count": { "type": "integer" },"skus": {"type": "nested","properties": {"title": { "type": "text", "analyzer": "ik_smart" }, "description": { "type": "text", "analyzer": "ik_smart"},"price": { "type": "scaled_float", "scaling_factor": 100 }}},"properties": {"type": "nested","properties": {"name": { "type": "keyword" }, "value": { "type": "keyword" }}}}

此时我们想查询在skus中存在或者properties中存在的某个匹配的值，skus和properties都是nested嵌套对象类型的，想要的匹配条件并非在一个nested中，如果使用查询

{"query": {"nested": {"path": "skus","query": {"bool": {"must": [{"multi_match": {"query": "256G","fields": ["skus.title","skus.description","properties.value"]}}]}}}}
}

来查询，并不能得到我们的预期（properties.name中有256G）。如果要硬写查询DSL那就更复杂了。我们可以使用copy_to来优化一下结构。

"properties": {"type": { "type": "keyword" } ,"title": { "type": "text", "analyzer": "ik_smart" }, "long_title": { "type": "text", "analyzer": "ik_smart" }, "category_id": { "type": "integer" },"category": { "type": "keyword" },"category_path": { "type": "keyword" },"description": { "type": "text", "analyzer": "ik_smart" },"price": { "type": "scaled_float", "scaling_factor": 100 },"on_sale": { "type": "boolean" },"rating": { "type": "float" },"sold_count": { "type": "integer" },"review_count": { "type": "integer" },"skus": {"type": "nested","properties": {"title": { "type": "text", "analyzer": "ik_smart", "copy_to": "skus_title" }, "description": { "type": "text", "analyzer": "ik_smart", "copy_to": "skus_description" },"price": { "type": "scaled_float", "scaling_factor": 100 }}},"properties": {"type": "nested","properties": {"name": { "type": "keyword" }, "value": { "type": "keyword", "copy_to": "properties_value" }}}}

给properties.title加上了copy_to参数，值是skus_title，Elasticsearch 就会把这个字段值复制到 skus_title 字段里，这样就可以在 multi_match 的 fields 里通过 skus_title 来匹配。skus.description 和 properties.name 同理。（修改了mapping后一定要记得重新同步数据）

{"query": {"bool": {"must": [{"multi_match": {"query": "256G","fields": ["skus_title","skus_description","properties_value"]}}]}}
}

使用此查询语句即可获得正确的数据。