RRF - Query language in Cosmos DB (in Azure and Fabric)

The RRF function returns a fused score by combining two or more scores provided by other functions.

Syntax

RRF(<function1>, <function2>, ..., <weights>)

Arguments

	Description
function1	A scoring function such as VectorDistance or FullTextScore.
function2	A scoring function such as VectorDistance or FullTextScore.
weights	An array of numbers defining an importance weight for each scoring function.

Return types

Returns a numeric value representing the fused score.

Examples

This section contains examples of how to use this query language construct.

Hybrid Search (vector similarity + BM25)

In this example, Hybrid Search combines FullTextScore and VectorDistance.

SELECT TOP 10 *
FROM c
ORDER BY RANK RRF(FullTextScore(c.text, "keyword"), VectorDistance(c.vector, [1,2,3]))

-- Example result not available (see documentation)

Weighted Hybrid Search

In this example, Hybrid Search uses weights for the scoring functions.

SELECT TOP 10 *
FROM c
ORDER BY RANK RRF(FullTextScore(c.text, "keyword"), VectorDistance(c.vector, [1,2,3]), [2,1])

-- Example result not available (see documentation)

Fusion with two FullTextScore functions

In this example, two FullTextScore functions are fused.

SELECT TOP 10 *
FROM c
ORDER BY RANK RRF(FullTextScore(c.text, "keyword1"), FullTextScore(c.text, "keyword2"))

-- Example result not available (see documentation)

Fusion with two VectorDistance functions

In this example, two VectorDistance functions are fused.

SELECT TOP 5 *
FROM c
ORDER BY RANK RRF(VectorDistance(c.vector1, [1,2,3]), VectorDistance(c.vector2, [2,2,4]))

-- Example result not available (see documentation)

Remarks

• This function requires enrollment in the Azure Cosmos DB NoSQL Full Text Search feature.
• Hybrid Search also requires enrollment in Azure Cosmos DB NoSQL Vector Search.
• This function requires a Full Text Index.
• This function can only be used in an ORDER BY RANK clause, and can't be combined with ORDER BY on other property paths.
• This function can’t be part of a projection (for example, SELECT FullTextScore(c.text, "keyword") AS Score FROM c is invalid).