文件名称：进阶-Aggregation框架-mongodb演示文档
文件大小：610KB
文件格式：PPT
更新时间：2024-05-15 13:26:34
mongo
进阶-Aggregation框架 管道操作符 $projectReshapes a document stream. $project can rename, add, or remove fields as well as create computed values and sub-documents. $matchFilters the document stream, and only allows matching documents to pass into the next pipeline stage. $match uses standard MongoDB queries. $limitRestricts the number of documents in an aggregation pipeline. $skipSkips over a specified number of documents from the pipeline and returns the rest. $unwindTakes an array of documents and returns them as a stream of documents. $groupGroups documents together for the purpose of calculating aggregate values based on a collection of documents. $sortTakes all input documents and returns them in a stream of sorted documents. $geoNearReturns an ordered stream of documents based on proximity to a geospatial point.