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Fabian Hueske commented on FLINK-4604: -------------------------------------- Hi [~anmu], I think we can implement and add support for {{SqlKind.SUM0}} as part of this issue. For that you have to implement a custom {{Sum0Aggregate}} which extends {{SumAggregate}} and overrides the {{prepare()}} method such that it does not initialize the aggregate with {{null}} but with {{0}} if the value is {{null}}. Next you have to fix the {{AggregateUtil}} and separate {{SqlSumEmptyIsZeroAggFunction}} from {{SqlSumAggFunction}} and initialize the new {{Sum0Aggregate}} and also allow for {{case SqlKind.SUM0 => true}} in {{DataSetAggregateRule}}. If I did not forget a place to add SUM0 support, that should do the trick. > Add support for standard deviation/variance > ------------------------------------------- > > Key: FLINK-4604 > URL: https://issues.apache.org/jira/browse/FLINK-4604 > Project: Flink > Issue Type: New Feature > Components: Table API & SQL > Reporter: Timo Walther > Assignee: Anton Mushin > Attachments: 1.jpg > > > Calcite's {{AggregateReduceFunctionsRule}} can convert SQL {{AVG, STDDEV_POP, > STDDEV_SAMP, VAR_POP, VAR_SAMP}} to sum/count functions. We should add, test > and document this rule. > If we also want to add this aggregates to Table API is up for discussion. -- This message was sent by Atlassian JIRA (v6.3.4#6332)