max_frequency()

Since 1.16.0

Get the maximum bound of the estimated frequency for a given value in a space-saving aggregate.

Samples

Find the maximum frequency of the value 3 in a column named value within the table value_test:

SELECT max_frequency(
    (SELECT mcv_agg(20, value) FROM value_test),
    3
);

Arguments

The syntax is:

max_frequency (
    agg SpaceSavingAggregate,
    value AnyElement
) RETURNS DOUBLE PRECISION

Name	Type	Default	Required	Description
agg	SpaceSavingAggregate	-	✔	A space-saving aggregate created using either freq_agg or mcv_agg
value	AnyElement	-	✔	The value to get the frequency of

Returns

Column	Type	Description
max_frequency	DOUBLE PRECISION	The maximum bound for the value’s estimated frequency. The maximum frequency might be 0 if the value’s frequency falls below the space-saving aggregate’s cut-off threshold. For more information, see freq_agg.