Fabian Hueske created FLINK-8951:
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Summary: Support OVER windows PARTITION BY (rounded) timestamp
Key: FLINK-8951
URL: https://issues.apache.org/jira/browse/FLINK-8951
Project: Flink
Issue Type: New Feature
Components: Table API & SQL
Reporter: Fabian Hueske
There are a few interesting use cases that can be addressed by queries that
follow the following pattern
{code:sql}
SELECT sensorId COUNT(*) OVER (PARTITION BY CEIL(rowtime TO HOUR) ORDER BY temp
ROWS BETWEEN UNBOUNDED preceding AND CURRENT ROW) FROM sensors
{code}
Such queries can be used to compute rolling cascading (tumbling) windows with
aggregates that are reset in regular intervals. This can be useful for TOP-K
per minute/hour/day queries.
Right now, such {{OVER}} windows are not supported, because we require that the
{{ORDER BY}} clause is defined on a timestamp (time indicator) attribute. In
order to support this kind of queries, we would require that the {{PARTITION
BY}} clause contains a timestamp (time indicator) attribute or a function that
is defined on it and which is monotonicity preserving. Once the optimizer
identifies this case, it could translate the query into a special
time-partitioned OVER window operator.
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