# _field_names field 该** _field_names **字段索引包含除 **null **之外的任何值的文档中每个字段的名称。 该字段通过 **[exists](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/query-dsl-exists-query.html) **查询以查找特定字段具有或不具有任何非空值的文档。 该** _field_names **字段的值可以在查询中被访问： # Example documents PUT my_index/my_type/1 { "title": "This is a document" } PUT my_index/my_type/2?refresh=true { "title": "This is another document", "body": "This document has a body" } GET my_index/_search { "query": { "terms": { "_field_names": [ "title" ] # 1 } } } | 1 | 在 **_field_names **字段上查询（参考 **[exists](https://www.elastic.co/guide/en/elasticsearch/reference/5.3/query-dsl-exists-query.html) **查询） |