[DOCS-6605] Enhanced Equality Match Meaning on $lookup Created: 16/Nov/15  Updated: 30/Oct/23  Resolved: 27/Apr/16

Status: Closed
Project: Documentation
Component/s: manual
Affects Version/s: None
Fix Version/s: Server_Docs_20231030

Type: Improvement Priority: Major - P3
Reporter: Kelsey Schubert Assignee: Steve Renaker (Inactive)
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Related
is related to SERVER-21469 $lookup is not working in case of the... Closed
Participants:
Days since reply: 7 years, 41 weeks, 6 days ago

 Description   

As described in Charlie's comment, if the localField is an array matching against a field inside will behave as null.

We may want to note this and recommend that users unwind first if their localFields are arrays.

https://docs.mongodb.org/master/reference/operator/aggregation/lookup/#pipe._S_lookup



 Comments   
Comment by Githook User [ 28/Apr/16 ]

Author:

{u'username': u'steveren', u'name': u'Steve Renaker', u'email': u'steve.renaker@mongodb.com'}

Message: DOCS-6605: changed headings for examples

Signed-off-by: kay <kay.kim@10gen.com>
Branch: master
https://github.com/mongodb/docs/commit/4a017ea0b81e7b616b5a4ee7c3e6a5fee0874fee

Comment by Githook User [ 28/Apr/16 ]

Author:

{u'username': u'steveren', u'name': u'Steve Renaker', u'email': u'steve.renaker@mongodb.com'}

Message: DOCS-6605: added $unwind example to $lookup page

Signed-off-by: kay <kay.kim@10gen.com>
Branch: master
https://github.com/mongodb/docs/commit/b6a2e00a5d79c7429482d40d7195f84e8619fa32

Comment by Githook User [ 28/Apr/16 ]

Author:

{u'username': u'steveren', u'name': u'Steve Renaker', u'email': u'steve.renaker@mongodb.com'}

Message: DOCS-6605: Enhanced Equality Match Meaning on $lookup

Signed-off-by: kay <kay.kim@10gen.com>
Branch: master
https://github.com/mongodb/docs/commit/a01cbebcbcb29b241a7645b5ec629001e76ec803

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