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From "sunjincheng (JIRA)" <j...@apache.org>
Subject [jira] [Created] (FLINK-6145) Add [non-partitioned] event time OVER ROWS BETWEEN x PRECEDING aggregation to SQL
Date Tue, 21 Mar 2017 16:09:41 GMT
sunjincheng created FLINK-6145:
----------------------------------

             Summary: Add [non-partitioned] event time OVER ROWS BETWEEN x PRECEDING aggregation
to SQL
                 Key: FLINK-6145
                 URL: https://issues.apache.org/jira/browse/FLINK-6145
             Project: Flink
          Issue Type: Sub-task
          Components: Table API & SQL
            Reporter: sunjincheng
            Assignee: sunjincheng


The goal of this issue is to add support for OVER ROWS aggregations on event time streams
to the SQL interface.

Queries similar to the following should be supported:
{code}
SELECT 
  a, 
  SUM(b) OVER (ORDER BY rowTime() ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) AS sumB,
  MIN(b) OVER (ORDER BY rowTime() ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) AS minB
FROM myStream
{code}

The following restrictions should initially apply:
- All OVER clauses in the same SELECT clause must be exactly the same.
- The ORDER BY clause may only have rowTime() as parameter. rowTime() is a parameterless scalar
function that just indicates event time mode.
- UNBOUNDED PRECEDING is not supported (see FLINK-5804)
- FOLLOWING is not supported.

The restrictions will be resolved in follow up issues. If we find that some of the restrictions
are trivial to address, we can add the functionality in this issue as well.

This issue includes:
- Design of the DataStream operator to compute OVER ROW aggregates
- Translation from Calcite's RelNode representation (LogicalProject with RexOver expression).



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