Flink SQL 1.10中ROW_NUMBER的使用

Mon, 06 Apr 2020 22:08:25 -0700 

HI,
我这边想要在滑动窗口之后做一个topN，于是就有下面的SQL：
-- 窗口聚合
create view window_v as
select
        member_id,
        category_id,
 HOP_END(ts, INTERVAL '10' SECOND, INTERVAL '30' MINUTE) as `time`,
        count(1) as c
from stream_t 
group by member_id, category_id, 
HOP(ts, INTERVAL '10' SECOND, INTERVAL '30' MINUTE);


-- 排序取top 20
SELECT
member_id,
        category_id,
        c,
        row_number() over (PARTITION BY member_id ORDER BY c) AS rn
FROM window_v;


但是执行异常：
Caused by: org.apache.flink.table.api.TableException: OVER windows' ordering in 
stream mode must be defined on a time attribute. at 
org.apache.flink.table.planner.plan.nodes.physical.stream.StreamExecOverAggregate.translateToPlanInternal(StreamExecOverAggregate.scala:195)
 at 
org.apache.flink.table.planner.plan.nodes.physical.stream.StreamExecOverAggregate.translateToPlanInternal(StreamExecOverAggregate.scala:56)
 at 
org.apache.flink.table.planner.plan.nodes.exec.ExecNode$class.translateToPlan(ExecNode.scala:58)
我看官网的TOPN例子中，order by 后面也可以是long型。难道row_number不能作用在窗口结果上？
Best,Xinghalo

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