Details
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New Feature
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Resolution: Done
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Major - P3
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None
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None
Description
Syntax
{
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$facet: {
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facetName1: [<stage1>, <stage2>, <stage3>],
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facetName2: [<stage4>, <stage5>, …],
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...
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}
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}
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Examples
> db.example.insert([
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{
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_id: "product1", |
avgReview: 4.3,
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price: 21,
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category: "TVs", |
title: "Sony 42 inch HDTV", |
attributes: [
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{name: "type", value: "HD"}, |
{name: "screen size", value: 42}, |
{name: "manufacturer", value: "Sony"}, |
...
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]
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}
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...
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])
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> db.example.aggregate([
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{$match: {category: "TVs"}}, // Match all relevant results. |
{$facet: {
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"Screen Sizes": [ |
{$unwind: "$attributes"}, |
{$match: {"attributes.name": "screen size"}}, |
{$group: {
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_id: { /* Use $switch to compute buckets for screen sizes */ }, |
count: {$sum: 1}
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}}
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],
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|
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"Manufacturer": [ |
{$match: {"attributes.name": "manufacturer"}}, |
{$group: {_id: "$attributes.value", count: {$sum: 1}}}, |
{$sort: {count: -1}}
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{$limit: 5}
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]
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}}
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])
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// Output.
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{
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"Screen Size": [ |
{_id: {min: MinKey, max: 32}, count: 32},
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{_id: {min: 32, max: 42}, count: 32},
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{_id: {min: 42, max: 50}, count: 33},
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{_id: {min: 50, max: MaxKey}, count: 33}
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],
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"Manufacturer": [ |
{_id: "Sony", count: 54}, |
{_id: "Samsung", count: 45}, |
{_id: "LG", count: 34}, |
{_id: "Sharp", count: 22}, |
{_id: "Vizio", count: 14}, |
]
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}
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Behavior
- names of sub-pipelines (keys in the document) must be unique.
- This is a blocking stage.
Attachments
Issue Links
- depends on
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SERVER-23654 Add $facet aggregation stage
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- Closed
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- is depended on by
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DRIVERS-297 Aggregation Framework Support for 3.4
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- Closed
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