assign time attribute after first window group when using Flink SQL

[Ivan Wang]

Hi all,



I'd like to use 2 window group in a chain in my program as below.



Table myTable = cTable
        .window(Tumble.*over*("15.seconds").on("timeMill").as("w1"))
        .groupBy("symbol, w1").select("w1.start as start, w1.end as end,
symbol, price.max as p_max, price.min as p_min")
        .window(Slide.*over*("150.rows").every("1.rows").on("start").as("w2"
))
        .groupBy("symbol, w2").select("w2.start, w2.end, symbol, p_max.max,
p_min.min")
        ;





However, it throws error: SlidingGroupWindow('w2, 'start, 150.rows, 1.rows)
is invalid: Sliding window expects a time attribute for grouping in a
stream environment.

         at
org.apache.flink.table.plan.logical.LogicalNode.failValidation(LogicalNode.scala:149)

         at
org.apache.flink.table.plan.logical.WindowAggregate.validate(operators.scala:658)

         at
org.apache.flink.table.api.WindowGroupedTable.select(table.scala:1159)

         at
org.apache.flink.table.api.WindowGroupedTable.select(table.scala:1179)

         at minno.gundam.ReadPattern.main(ReadPattern.java:156)



Is there any way to assign time attribute after the first groupBy (w1)?



Thanks

Ivan