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Type: Improvement
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Resolution: Done
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Priority: Major - P3
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Affects Version/s: None
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Component/s: Aggregation Framework
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Minor Change
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Query 11 (03/14/16), Query 12 (04/04/16), Query 13 (04/22/16), Query 14 (05/13/16), Query 15 (06/03/16), Query 16 (06/24/16)
There is currently no way to easily specify that project stage keep all fields except for a particular one (with exception of _id).
This can be helpful to limit the amount of data returned when some aggregation also needs to be done.
Examples
// Exclude a single field. > db.example.insert([ {_id: 0, a: 1} ]); > db.example.aggregate([{$project: {a: 0}}]) {_id: 0} > db.example.aggregate([{$project: {a: false}}]) // Means the same thing as above. {_id: 0} // Exclude a nested field. > db.example.drop() > db.example.insert([ {_id: 0, a: {b: 1, c: 1}} ]); > db.example.aggregate([{$project: {'a.b': 0}}]) {_id: 0, a: {c: 1}} > db.example.aggregate([{$project: {a: {b: 0}}}]) // Means the same thing as above. {_id: 0, a: {c: 1}} // Exclude a nested field from an array. > db.example.drop() > db.example.insert([ {_id: 0, a: [{b: 1, c: 1}, {b: 2, c: 2}]} ]); > db.example.aggregate([{$project: {'a.b': 0}}]) {_id: 0, a: [{c: 1}, {c: 2}]} > db.example.aggregate([{$project: {a: {b: 0}}}]) // Means the same thing as above. {_id: 0, a: [{c: 1}, {c: 2}]}
- duplicates
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SERVER-22787 Add $lookup.excludeLocalField to exclude local field from output
- Backlog
- is depended on by
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SERVER-22436 Allow parsing of string literals in aggregation's $project
- Closed
- is duplicated by
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SERVER-23411 Inconsistent results when setting a nested field in $project
- Closed
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SERVER-22436 Allow parsing of string literals in aggregation's $project
- Closed
- is related to
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SERVER-30633 Large performance regression for large aggregation queries
- Closed
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DRIVERS-297 Aggregation Framework Support for 3.4
- Closed
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SERVER-24921 No way to $project out just the _id field in aggregation
- Closed
- related to
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SERVER-6714 Array in input doc schema incorrectly affects $project output
- Closed
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SERVER-23411 Inconsistent results when setting a nested field in $project
- Closed
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CSHARP-1598 allow exclusion in $project stage
- Closed
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JAVA-2148 Ensure proper builder support for exclusions in the $project stage of an aggregation pipeline
- Closed
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SERVER-5781 Implement $addFields aggregation stage for using expression language to add new fields to a document
- Closed