APPROX_PERCENTILE() GROUP BY ...

All functions > GROUP BY > APPROX_PERCENTILE() GROUP BY ...

Returns the approximate value at the given percentile.

Syntax

APPROX_PERCENTILE(expr, percentile)
 [ FILTER (WHERE condition) ]
  [ GROUP BY feature [, feature ...] ]

APPROX_PERCENTILE(expr, percentile)
 [ FILTER (WHERE condition) ]
  [ GROUP BY feature [, feature ...] ]

Notes

• Uses approximate algorithms for efficient computation on large datasets
• Percentile must be between 0.0 and 1.0 (e.g. 0.5 for median)
• NULL values are excluded from the calculation
• Returns NULL if all values are NULL or group is empty

Examples

SELECT
    -- Approximate median (0.5 quantile)
    f1 := ZIP(ARRAY(1, 2, 3, 4, 5) AS value).TRANSFORM(
        SELECT APPROX_PERCENTILE(value, 0.5)
    ).UNWRAP_ONE()
;