Details
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Type:
Task
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Status: Closed
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Priority:
Major - P3
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Resolution: Fixed
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Affects Version/s: None
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Fix Version/s: 4.9.0
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Labels:None
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Last comment by Customer:true
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Story Points:5
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Epic Link:
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Sprint:ServerDocs2020: Feb2 - Feb9, ServerDocs2020: Feb9 - Feb16, ServerDocs2020: Feb16 - Feb23, ServerDocs2020: Feb23 - Mar2
Description
Description
Previously, to determine the matching documents from the joined collection, $lookup accepted either the localField and foreignField arguments to perform an equality match or a pipeline to apply to the joined collection. After this change, the localField/foreignField arguments and the pipeline/let arguments can be used together when specifying a $lookup. For examples, see the syntax doc in WRITING-7251.
Description of Linked Ticket
This proposes closing SERVER-29376 and instead allowing combination of both, localField and foreignField and expressive pipeline.
{$lookup:{from:"other",
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localField:"l",
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foreignField:"f",
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as:"fromOther"
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[, pipeline: [ ... ] ] /* optionally add a pipeline to apply *after* equality join */
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This allows preserving the non-expressive lookup equality semantics with additional flexibility of using anything along with it like $sort and $limit etc.
Scope of changes
Impact to Other Docs
MVP (Work and Date)
Resources (Scope or Design Docs, Invision, etc.)
Attachments
Issue Links
- documents
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SERVER-34927 allow localField and foreignField with more expressive $lookup pipeline
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- Closed
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