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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: 2.4.3
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Component/s: Aggregation Framework
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Labels:None
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Fully Compatible
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Quint Iteration 7, QuInt 8 08/28/15
Make the following accumulators available as expressions: $stdDevSamp, $stdDevPop, $avg, $min, $max, and $sum.
As expressions, available in the $project stage, these operators can take either:
- A single argument: <accumulator> : <arg>
- Multiple arguments: <accumulator> : [ <arg1>, <arg2>, ... ]
Single Argument: <arg>
If the argument is an array, the accumulator operates on the elements of the array to return a single value. If the argument is not an array, the accumulator operates on the single argument.
Multiple arguments: [ <arg1>, <arg2>, ... ]
The accumulator operates on the arguments to return a single value.
If any of the argments is an array, the accumulator does not traverse into the array elements.
Non-numerical arguments
When used as part of the $project stage, $sum, $avg, $stdDevSamp, and $stdDevPop ignore non-numerical arguments.
Original request:
{'$group': {
'_id': {
'grp_0': '$ses.usr',
'grp_1': '$ses._id'
},
'agg_0': {'$sum': {'$subtract': [
{'$cond': [{'$lt': ['$ses.e', E]},
'$ses.e',
E]},
{'$cond': [{'$gt': ['$ses.s', S]},
'$ses.s',
S]}
]}
}
}}
you can write:
{'$group':
{
'_id': {
'grp_0': '$ses.usr',
'grp_1': '$ses._id'
},
'agg_0': {'$sum': {'$subtract': [
{'$min': ['$ses.e', E]},
{'$max': ['$ses.s', S]}
]}
}
}
}
- is duplicated by
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SERVER-10626 Support numeric arrays as input to $add in aggregation's $project
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- Closed
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- Closed
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- Closed
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- Closed
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- is related to
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DRIVERS-234 Aggregation Builder Support for 3.2
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- Closed
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- related to
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- Closed
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