RRF (NoSQL query)

APPLIES TO: NoSQL

This system function is used to combine two or more scores provided by other functions.

Syntax

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

	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.

This is an example of Hybrid Search (vector similarity search + BM25 full text scoring).

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

This example shows fusion with two FullTextScore functions

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

This example shows fusion with two VectorDistance functions

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

This example shows fusion with two VectorDistance functions

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.