APPROX_COUNT_DISTINCT_EACH

Approximates the number of distinct values for each given group.

Syntax

APPROX_COUNT_DISTINCT([MAX_VALUES,] GROUP, VALUE)

Arguments

MAX_VALUES

Type: integer

Default: no limit

(Optional) The maximum number of groups. Groups beyond this amount are discarded.

In some cases, discarding groups via this option may cause some data to be discarded from groups that would otherwise have been kept.

GROUP

Type: any

The field by which to group the results.

VALUE

Type: any

The field to count distinct values relative to each group.

Returns

Type: array

Returns an array of key-value pairs where each GROUP is matched to the approximate number of distinct values VALUE seen for that group.

If all input values are null, zero is returned.