This documentation is related to an older version of Firebolt. For the most current documentation, see Firebolt documentation.

HLL_COUNT_EXTRACT

Extracts a cardinality estimate of a single HLL++ sketch.

If the sketch is NULL, this function returns a cardinality estimate of 0.

Syntax

HLL_COUNT_EXTRACT ( <expression> )

Parameters

Return Type

BIGINT

Example

SELECT
    HLL_COUNT_EXTRACT(hll_sketches) as count_distinct, hll_sketches
FROM
    sketch_table;

Returns:

The cardinality estimates of HLL++ sketches represented as data type BYTEA.