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rollup(TimeWeightSummary)
rollup(
tws TimeWeightSummary
) RETURNS TimeWeightSummaryAn aggregate to compute a combined TimeWeightSummary from a series of
non-overlapping TimeWeightSummaries. Overlapping TimeWeightSummaries causes
errors.
For more information about time-weighted average functions, see the hyperfunctions documentation.
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
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