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Type:
Improvement
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Resolution: Done
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Priority:
Major - P3
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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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Fully Compatible
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Quint Iteration 4, Quint Iteration 5
I need to count the number of duplicate IDs that occur across all documents in a collection. However, this very simple aggregation is complicated by the fact that the IDs in question may appear in multiple fields in the input document.
Suppose I have input documents like the one below:
{
a : [1, 2, 3],
b : [2, 4, 5]
}
I'd like to transform this to a document that looks like:
{
c : [1, 2, 3, 2, 4, 5]
}
From this point, it is straightforward to unwind and group on c to get to the desired result.
The above transformation is similar to what would be achieved using the $setUnion operator, but here I do not want to filter out duplicate values.
Therefore, this request is for an operator similar to $setUnion but which does not filter out duplicate values.
- is duplicated by
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- Closed
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- is related to
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SERVER-17258 Add $reduce expression operator for rollup of arrays
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- Closed
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- related to
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- Closed
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DRIVERS-234 Aggregation Builder Support for 3.2
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- Closed
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