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Type:
Bug
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Resolution: Duplicate
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Priority:
Major - P3
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None
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Affects Version/s: 3.2.9
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Component/s: Aggregation Framework
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None
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ALL
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here's some data:
> db.scratch.find()
{ "_id" : ObjectId("57e0bac25e54b80da88af731"), "a" : "baz" }
{ "_id" : ObjectId("57e0bac75e54b80da88af732"), "a" : "foo", "b" : "bar" }
here's a pipeline, desired effect is to concat a and b if i have both fields, or just use a if b isn't present:
> db.scratch.aggregate([{$project: {ab: {$cond: [{$eq: ['$b', null]}, '$a', {$concat: ['$a', ':', '$b']}]}}}])
{ "_id" : ObjectId("57e0bac25e54b80da88af731"), "ab" : null }
{ "_id" : ObjectId("57e0bac75e54b80da88af732"), "ab" : "foo:bar" }
but when b is not present and i want a i get null... ?!
- duplicates
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- Backlog
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