rollup(TimeWeightSummary
)
rollup(
tws TimeWeightSummary
) RETURNS TimeWeightSummary
An aggregate to compute a combined TimeWeightSummary
from a series of non-overlapping TimeWeightSummaries
. Overlapping TimeWeightSummaries
will cause errors. See Notes on Parallelism and Ordering for more information.
Required arguments
Name | Type | Description |
---|---|---|
tws | TimeWeightSummary | The input TimeWeightSummary from a previous time_weight call, often from a continuous aggregate |
Returns
Column | Type | Description |
---|---|---|
time_weight | TimeWeightSummary | A TimeWeightSummary object that can be passed to other functions within the time weighting API |
Sample usage
WITH t as (
SELECT
date_trunc('day', ts) as dt,
time_weight('Linear', ts, val) AS tw -- get a time weight summary
FROM foo
WHERE measure_id = 10
GROUP BY date_trunc('day', ts)
), q as (
SELECT rollup(tw) AS full_tw -- do a second level of aggregation to get the full time weighted average
FROM t
)
SELECT
dt,
average(tw), -- extract the average from the time weight summary
average(tw) / (SELECT average(full_tw) FROM q LIMIT 1) as normalized -- get the normalized average
FROM t;
当前内容版权归 TimescaleDB 或其关联方所有,如需对内容或内容相关联开源项目进行关注与资助,请访问 TimescaleDB .