mongodb select one field
To return all documents in a collection, omit this parameter or pass an empty ..... The query uses dot notation to access fields in an embedded document: copy. ,Omit this parameter to return all fields in the matching document. The <boolean> can be one of the following include or exclude values: 1 or true to include. The findOne() method always includes the _id field even if the field is not explicitly spec
| 相關軟體 MongoDB 資訊 | |
|---|---|
 mongodb select one field 相關參考資料
db.collection.distinct() — MongoDB Manual
跳到 Return Distinct Values for an Array Field. - The following example returns the distinct values for the field sizes from all documents in the ... https://docs.mongodb.com db.collection.find() — MongoDB Manual
To return all documents in a collection, omit this parameter or pass an empty ..... The query uses dot notation to access fields in an embedded document: copy. https://docs.mongodb.com db.collection.findOne() — MongoDB Manual
Omit this parameter to return all fields in the matching document. The <boolean> can be one of the following include or exclude values: 1 or true to include. The findOne() method always includes... https://docs.mongodb.com How to select a single field in MongoDB? - Stack Overflow
From the MongoDB docs: A projection can explicitly include several fields. In the following operation, find() method returns all documents that match the query. In the result set, only the item and qt... https://stackoverflow.com List all values of a certain field in mongodb - Stack Overflow
db.collection.distinct('x'). should give you an array of unique values for that field. ... of docs, containing just it's x value... db.collection.find( }, x: 1, y: 0, _id:0 } ). https://stackoverflow.com mongo .find return specific field only for all user - Stack Overflow
Please take a look at the documentation. You will notice that find has an optional second parameter called "projection". This parameter is used to state which ... https://stackoverflow.com Mongodb query with fields in the same documents - Stack Overflow
Still, such low-selectivity fields don't yield good index performance, because he .... In a find(), or the $match phase of aggregation, $eq takes a single value, and ... https://stackoverflow.com Project Fields to Return from Query - MongoDB Documentation
To limit the amount of data that MongoDB sends to applications, you can include a projection document to specify or restrict fields to return. This page provides examples of query operations with proj... https://docs.mongodb.com |