MAX() OVER ...
All functions > WINDOW FUNCTION > MAX() OVER ...
Returns the maximum value in the window frame.
Syntax
MAX(expr) [FILTER (WHERE condition) | WITHIN (WHERE condition)] OVER ([PARTITION BY expr [, ...]] [ORDER BY sort_item [, ...]] [ROWS|RANGE|GROUPS frame])
Notes
- Finds maximum value over a window of rows
- Useful for running maximums and comparisons
- Returns same type as input expression
- NULL values are ignored in the calculation
See also
Examples
FeatureQL
SELECT
-- Running maximum (v permuted so output is not the same array as v)
f1 := ZIP(ARRAY(1, 2, 3, 4) AS id, ARRAY(30, 10, 20, 5) AS v).TRANSFORM(
SELECT MAX(v) OVER (ORDER BY id ASC)
).UNWRAP(),
-- Running maximum counting only rows where v > 15 (10 and 5 excluded from the frame)
f2 := ZIP(ARRAY(1, 2, 3, 4) AS id, ARRAY(30, 10, 20, 5) AS v).TRANSFORM(
SELECT MAX(v) FILTER (WHERE v > 15) OVER (ORDER BY id ASC)
).UNWRAP()
;Result
| f1 ARRAY | f2 ARRAY |
|---|---|
| [30, 30, 30, 30] | [30, 30, 30, 30] |