Hi Tao, DISTINCT aggregates in group windows are not supported yet. There's currently a discussion on the dev mailing list about this feature [1].
Since we are only a few days before the feature freeze of Flink 1.5.0, it might be included in 1.6.0, about 4-5 months from now. As a workaround, you can implement a custom user-defined aggregation function [2] that performs distinct counts. Cheers, Fabian [1] https://lists.apache.org/thread.html/4bdf66ce56ad5561461c8947203ccefa3fe2e4a1e48e29236f1bb8fc@%3Cdev.flink.apache.org%3E [2] https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/table/udfs.html#aggregation-functions 2018-02-15 0:15 GMT+01:00 xiatao123 <t...@udacity.com>: > SELECT TUMBLE_START(event_timestamp, INTERVAL '1' HOUR), COUNT(DISTINCT > session), COUNT(DISTINCT user_id), SUM(duration), SUM(num_interactions) > FROM > unified_events GROUP BY TUMBLE(event_timestamp, INTERVAL '1' HOUR) > > I have the above statement my flink query running on Flink 1.3.2, but got > the error message Caused by: org.apache.flink.table.api.TableException: > Cannot generate a valid execution plan for the given query > > Is the feature supported yet? if Yes, in which version of flink? If no, any > timeline to support it? > > Thanks, > Tao > > > > -- > Sent from: http://apache-flink-user-mailing-list-archive.2336050. > n4.nabble.com/ >
