Text Search in the Aggregation Pipeline聚合管道中的文本搜索

Calculate the Total Views for Articles that Contains a Word计算包含单词的文章的总视图

The following aggregation searches for the term cake in the $match stage and calculates the total views for the matching documents in the $group stage.以下聚合在$match阶段中搜索术语cake，并计算$group阶段中匹配文档的总视图。

db.articles.aggregate(
   [
     { $match: { $text: { $search: "cake" } } },
     { $group: { _id: null, views: { $sum: "$views" } } }
   ]
)

Return Results Sorted by Text Search Score返回按文本搜索分数排序的结果

To sort by the text search score, include a {$meta: "textScore"} expression in the $sort stage. 要按文本搜索分数排序，请在$sort阶段包含{$meta: "textScore"}表达式。The following example matches on either the term cake or tea, sorts by the textScore in descending order, and returns only the title field in the results set.下面的示例匹配术语cake或tea，按textScore降序排序，并仅返回结果集中的title字段。

db.articles.aggregate(
   [
     { $match: { $text: { $search: "cake tea" } } },
     { $sort: { score: { $meta: "textScore" } } },
     { $project: { title: 1, _id: 0 } }
   ]
)

The specified metadata determines the sort order. 指定的元数据确定排序顺序。For example, the "textScore" metadata sorts in descending order. 例如，"textScore"元数据按降序排序。See $meta for more information on metadata as well as an example of overriding the default sort order of the metadata.有关元数据的更多信息以及重写元数据的默认排序顺序的示例，请参阅$meta。

Match on Text Score文本分数匹配

The "textScore" metadata is available for projections, sorts, and conditions subsequent the $match stage that includes the $text operation."textScore"元数据可用于包括$text操作的$match阶段之后的预测、排序和条件。

The following example matches on either the term cake or tea, projects the title and the score fields, and then returns only those documents with a score greater than 1.0.下面的示例匹配术语cake或tea，投影title和score字段，然后仅返回score大于1.0的文档。

db.articles.aggregate(
   [
     { $match: { $text: { $search: "cake tea" } } },
     { $project: { title: 1, _id: 0, score: { $meta: "textScore" } } },
     { $match: { score: { $gt: 1.0 } } }
   ]
)

Specify a Language for Text Search指定用于文本搜索的语言

The following aggregation searches in spanish for documents that contain the term saber but not the term claro in the $match stage and calculates the total views for the matching documents in the $group stage.以下聚合以西班牙语搜索$match阶段中包含术语saber但不包含术语claro的文档，并计算$group阶段中匹配文档的总视图。

db.articles.aggregate(
   [
     { $match: { $text: { $search: "saber -claro", $language: "es" } } },
     { $group: { _id: null, views: { $sum: "$views" } } }
   ]
)