VAR_POP() OVER ...
All functions > WINDOW FUNCTION > VAR_POP() OVER ...
Returns the population variance over the window frame.
Syntax
VAR_POP(expr) [FILTER (WHERE condition) | WITHIN (WHERE condition)] OVER ([PARTITION BY expr [, ...]] [ORDER BY sort_item [, ...]] [ROWS|RANGE|GROUPS frame])
Notes
- Computes population variance (divides by N) over a window of rows
- NULL values are ignored in the calculation
See also
Examples
FeatureQL
SELECT
-- Population variance of v in the frame (id is only the sort key)
f1 := ZIP(ARRAY(1, 2, 3, 4) AS id, ARRAY(30, 10, 20, 5) AS v).TRANSFORM(
SELECT VAR_POP(CAST(v AS DOUBLE)) OVER (ORDER BY id ASC).ROUND(2)
).UNWRAP(),
-- Population variance 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 VAR_POP(CAST(v AS DOUBLE)) FILTER (WHERE v > 15) OVER (ORDER BY id ASC).ROUND(
2
)
).UNWRAP()
;Result
| f1 ARRAY | f2 ARRAY |
|---|---|
| [0.00, 100.00, 66.67, 92.19] | [0.00, 0.00, 25.00, 25.00] |