-
Type: New Feature
-
Resolution: Duplicate
-
Priority: Major - P3
-
None
-
Affects Version/s: 3.2.0
-
Component/s: Aggregation Framework
-
Query
-
Fully Compatible
The Aggregation Framework $lookup stage currently only allows single key foreign key equality lookups in a joined collection. This does not allow opportunities where the uniqueness of a joined collection requires multiple keys in the joined collection.
One of the earlier syntaxes for $lookup had the following subdocument, which is consistent with find syntax, and would naturally allow multiple key joins:
on :
{ sourceKey1 : $foreignKey1 }or for multiple keys:
on :
{ sourceKey1 : $foreignKey1, sourceKey2 : $foreignKey2 }- duplicates
-
SERVER-29072 Add support for $lookup into a sub-pipeline
- Closed