You are currently browsing legacy 4.1 version of documentation. Click here to switch to the newest 4.2 version.

We can help you with migration to the latest RavenDB

Contact Us Now
see on GitHub

Session: Querying: How to Perform a Faceted (Aggregated) Search

To execute facet (aggregation) query using the session query() method, use the aggregateBy() or aggregateUsing() methods. This will scope you to the aggregation query builder where you will be allowed to define single or multiple facets for the query using a straightforward and fluent API.

Syntax

query.aggregateBy(facetBuilder);
query.aggregateBy(facet);
query.aggregateBy(...facets);
query.aggregateUsing(facetSetupDocumentId);

Parameters
facet FacetBase FacetBase implementation defining the scope of the facet and its options (either Facet or RangeFacet)
facets ...FacetBase Items containing FacetBase implementations
facetBuilder (builder) => void Builder with a fluent API that constructs a FacetBase instance
facetSetupDocumentId string ID of a document containing FacetSetup

Facet & RangeFacet

Facet vs RangeFacet

RangeFacet allows you to split the results of the calculations into several ranges, in contrast to Facet where whole spectrum of results will be used to generate a single outcome.

FacetAggregation is one of the following:

  • "None"

  • "Max"

  • "Min"

  • "Average"

  • "Sum"

Facet

Fields
fieldName string
options FacetOptions
aggregrations Map<FieldAggregration, string>
displayFieldName string

RangeFacet

Fields
ranges string[]
options FacetOptions
aggregrations Map<FieldAggregration, string>
displayFieldName string

Builder

facetBuilder.byRanges(range, ...ranges);
facetBuilder.byField(fieldName);

facetBuilder.withDisplayName(displayName);

facetBuilder.withOptions(options);

facetBuilder.sumOn(path);
facetBuilder.minOn(path);
facetBuilder.maxOn(path);
facetBuilder.averageOn(path);

Parameters
path string Points to the index field that should be used for operation (byRanges(), byField()) or to document field that should be used for aggregation (sumOn(), minOn(), maxOn(), averageOn())
fieldName string Points to the index field that should be used for operation (byRanges(), byField()) or to document field that should be used for aggregation (sumOn(), minOn(), maxOn(), averageOn())
displayName string If set, results of a facet will be returned under this name
options object Non-default options that should be used for operation
  termSortMode string Indicates how terms should be sorted (ValueAsc, ValueDesc, CountAsc, CountDesc)
  includeRemainingTerms boolean Indicates if remaining terms should be included in results
  start number Used to skip given number of facet results in the outcome
  pageSize number Used to limit facet results to the given value

Example I

const facetOptions = {
    termSortMode: "CountDesc"
};

const facet1 = new Facet();
facet1.fieldName = "manufacturer";
facet1.options = facetOptions;

const facet2 = new RangeFacet();
facet2.ranges = [ 
    "cost < 200",
    "cost between 200 and 400",
    "cost between 400 and 600",
    "cost between 600 and 800",
    "cost >= 800"
];
facet2.aggregations = new Map([["Average", "cost"]]);

const facet3 = new RangeFacet();
facet3.ranges = [ 
    "megapixels < 3",
    "megapixels between 3 and 7",
    "megapixels between 7 and 10",
    "megapixels >= 10"
];

const facets = await session
    .query({ indexName: "Camera/Costs" })
    .aggregateBy(facet1)
    .andAggregateBy(facet2)
    .andAggregateBy(facet3)
    .execute();
from index 'Camera/Costs' 
select 
facet(manufacturer), 
facet(cost < 200, cost >= 200 AND cost < 400, cost >= 400 AND cost < 600, cost >= 600 AND cost < 800, cost >= 800),
facet(megapixels < 3, megapixels >= 3 AND megapixels < 7, megapixels >= 7 AND megapixels < 10, megapixels >= 10)

Example II

const options = { termSortMode: "CountDesc" };

const costBuilder = RangeBuilder.forPath("cost");
const megapixelsBuilder = RangeBuilder.forPath("megapixels");

const facetResult = await session
    .query({ indexName: "Camera/Costs" })
    .aggregateBy(builder => builder
        .byField("manufacturer")
        .withOptions(options))
    .andAggregateBy(builder => builder
        .byRanges(
            costBuilder.isLessThan(200),
            costBuilder.isGreaterThanOrEqualTo(200).isLessThan(400),
            costBuilder.isGreaterThanOrEqualTo(400).isLessThan(600),
            costBuilder.isGreaterThanOrEqualTo(600).isLessThan(800),
            costBuilder.isGreaterThanOrEqualTo(800))
        .averageOn("cost"))
    .andAggregateBy(builder => builder
        .byRanges(
            megapixelsBuilder.isLessThan(3),
            megapixelsBuilder.isGreaterThanOrEqualTo(3).isLessThan(7),
            megapixelsBuilder.isGreaterThanOrEqualTo(7).isLessThan(10),
            megapixelsBuilder.isGreaterThanOrEqualTo(10)
        ))
    .execute();
from index 'Camera/Costs' 
select 
facet(manufacturer), 
facet(cost < 200, cost >= 200 and cost < 400, cost >= 400 and cost < 600, cost >= 600 and cost < 800, cost >= 800),
facet(megapixels < 3, megapixels >= 3 AND megapixels < 7, megapixels >= 7 AND megapixels < 10, megapixels >= 10)

Example III

const facetSetup = new FacetSetup();

const facetManufacturer = new Facet();
facetManufacturer.fieldName = "manufacturer";
facetSetup.facets = [ facetManufacturer ];

const cameraFacet = new RangeFacet();
cameraFacet.ranges = [
    "cost < 200",
    "cost between 200 and 400",
    "cost between 400 and 600",
    "cost between 600 and 800",
    "cost >= 800"
];

const megapixelsFacet = new RangeFacet();
megapixelsFacet.ranges = [
    "megapixels < 3",
    "megapixels between 3 and 7",
    "megapixels between 7 and 10",
    "megapixels >= 10"
];

facetSetup.rangeFacets = [ cameraFacet, megapixelsFacet ];

await session.store(facetSetup, "facets/CameraFacets");
await session.saveChanges();

const facets = await session
    .query({ indexName: "Camera/Costs" })
    .aggregateUsing("facets/CameraFacets")
    .execute();
from index 'Camera/Costs' 
select facet(id('facets/CameraFacets'))

Remarks

Warning

aggregateBy() only supports aggregation by a single field. If you want to aggregate by multiple fields, you need to emit a single field that contains all values.