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Type:
Improvement
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Resolution: Duplicate
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Priority:
Minor - P4
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None
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Affects Version/s: None
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Component/s: Aggregation Framework
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None
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Query
i have a situation where i have arrays in collection documents that i want to aggregate into a "union" array on a result, something like:
{key: 1, numbers: [1, 2, 3]}
{key: 1, numbers: [2, 3, 4]}
and i would like to do something like:
aggregate(
[
{$group: {_id: '$key', numbers: {$setUnion: '$numbers'}}}
]
)
and have the result be:
{_id: 1, numbers: [1, 2, 3, 4]}
right now i would have to {$unwind: '$numbers'}
first and then use {$addToSet: '$numbers'} which is more steps, and seems like it could add significant overhead with high volume arrays and bulkier documents.
- duplicates
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SERVER-16284 Allow for $pushall / $push with $each to allow pushing all elements of array in $group
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- Closed
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- is related to
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SERVER-27644 distinct on a view doesn't "flatten" array members
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- Closed
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