COUNTD_APPROX

    Syntax

    COUNTD_APPROX( value )
    
    COUNTD_APPROX( value
                   [ FIXED ... | INCLUDE ... | EXCLUDE ... ]
                   [ BEFORE FILTER BY ... ]
                 )
    

    More info:

    Description

    Returns the approximate number of unique values in the group. Faster than COUNTD, but doesn't guarantee accuracy.

    Argument types:

    • valueAny

    Return type: Integer

    Example

    COUNTD_APPROX([ClienID])
    

    Data source support

    ClickHouse 19.13.