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https://issues.apache.org/jira/browse/FLINK-11220?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16735450#comment-16735450
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sunjincheng commented on FLINK-11220:
-------------------------------------
Thanks Fabian,
I totally agree manually assigning timestamps and watermarks should be the last
resort. +1
I think both `Add a query configuration` and using `CAST` will confuse users.
Users will ask why they need to add this configuration or why are all row-time
columns, one do not needs to be CAST, and others must need to be CAST？
I like the idea of add a method (or method variant) to choose the timestamp
that should be forwarded. In table API maybe easy, something like :
`select('orderTime, 'payTime).withTimestamp('payTime)`. But in SQL is very
difficult，I can see using hints to carry information, but the hints are usually
used for optimization, and using it in set`timestamp` is a bit hard to
understand. Maybe I don't fully understand what you mean.
can you explain more details?
BTW: From my points of view before toDataStream user do not need assigning
timestamps and watermarks in SQL/TableAPI, and after toDataStream, user will
using the DataStreamAPI and they should know well about
`assignTimestampsAndWatermarks`.
Best,
Jincheng
> Can not Select row time field in JOIN query
> -------------------------------------------
>
> Key: FLINK-11220
> URL: https://issues.apache.org/jira/browse/FLINK-11220
> Project: Flink
> Issue Type: Bug
> Components: Table API & SQL
> Affects Versions: 1.8.0
> Reporter: sunjincheng
> Priority: Major
>
> SQL:
> {code:java}
> Orders...toTable(tEnv, 'orderId, 'orderTime.rowtime)
> Payment...toTable(tEnv, 'orderId, 'payTime.rowtime)
> SELECT orderTime, o.orderId, payTime
> FROM Orders AS o JOIN Payment AS p
> ON o.orderId = p.orderId AND
> p.payTime BETWEEN orderTime AND orderTime + INTERVAL '1' HOUR
> {code}
> Execption:
> {code:java}
> org.apache.flink.table.api.TableException: Found more than one rowtime field:
> [orderTime, payTime] in the table that should be converted to a DataStream.
> Please select the rowtime field that should be used as event-time timestamp
> for the DataStream by casting all other fields to TIMESTAMP.
> at
> org.apache.flink.table.api.StreamTableEnvironment.translate(StreamTableEnvironment.scala:906)
> {code}
> The reason for the error is that we have 2 time fields `orderTime` and
> `payTime`. I think we do not need throw the exception, and we can remove
> the logic of `plan.process(new OutputRowtimeProcessFunction[A](conversion,
> rowtimeFields.head.getIndex))`, if we want using the timestamp after
> toDataSteram, we should using `assignTimestampsAndWatermarks()`.
> What do you think ? [~twalthr] [~fhueske]
>
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