-
Type: New Feature
-
Resolution: Duplicate
-
Priority: Major - P3
-
None
-
Affects Version/s: None
-
Component/s: Aggregation Framework
-
None
another way to implement cross-collections joins.
ex: 2 collections: Books and Authors.
book = { _id:1, title: 'A', author_id: 1 } author = { _id: 1, name: 'Me' } db.aggregate( {$collection: 'book', $match: ...}, {$collection: 'author', $match: ...}, ... {$group: ...}, {$project: ...} )
in result (example too):
books_with_authors = [ {_id:1, title: 'A', author: { _id: 1, name: 'Me' }}, ... ]
- duplicates
-
SERVER-19095 $lookup
- Closed