If the query bar displays the Project option, you can specify which fields to return in the resulting data. By default, all fields are returned.
To set a projection:
In the Query Bar, click Options.
Enter the projection document into the Project field.
- To include fields:
Specify the field name and set to
1
in the project document.Example
{ year: 1, name: 1 } Only the fields specified in the project document are returned. The
_id
field is returned unless it is set to0
in the Project document.- To exclude fields:
Specify the field name and set to
0
in the project document.Example
{ year: 0, name: 0 } All fields except for the fields specified in the project document are returned.
As you type, the Find button is disabled and the Project label turns red until a valid query is entered.
Click Find to run the query and view the updated results.
Note
For query result sets larger than 1000 documents, Compass shows a subset of the results. Otherwise, Compass shows the entire result set.
For details on sampling, see Sampling.
How Does the Compass Query Compare to MongoDB and SQL Queries?
$project
corresponds to choosing specific fields to return
in a SQL SELECT
statement.
Example
You have 3,235 articles. You would like to see only the headlines and authors of those articles.
- SQL
SELECT headline, author FROM article; - MongoDB Aggregation
db.article.aggregate( { $project : { headline : 1, author : 1 } } ); - Compass Project Option
{ headline : 1, author : 1 }
Learn More
To learn how project works, see the project
entry in the
MongoDB Manual.