Hi! As far as I know, returning an array from the getValue method containing external data format is OK. Flink will do the conversion for you.
Are you faced with any exception when using this array_agg? If yes what's the exception stack? You can also open a JIRA ticket to require a built-in support for array_agg, as this function exists in many data ware houses. Yuval Itzchakov <yuva...@gmail.com> 于2021年8月23日周一 下午7:38写道： > Hi, > > I'm trying to implement a generic ARRAY_AGG UDF function (identical to the > one that exists in many data WHs, e.g > https://docs.snowflake.com/en/sql-reference/functions/array_agg.html) to > utilize in Flink SQL. > > Taking reference from CollectAggFunction > <https://github.com/apache/flink/blob/master/flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/aggfunctions/CollectAggFunction.java>, > I tried using ArrayData to generate a GenericArrayData as an output type. > The problem with is I need a way to convert from the external format being > used in the UDF (e.g String, Integer) to the internal representation > required by Flink (i.e. StringData). I haven't found a straight way of > going about that. > > Here is a gist of the implementation > <https://gist.github.com/YuvalItzchakov/5cc7b076d31d73e5c1f9b7b72b3c624b>. > Would appreciate any help on how to tackle this. > > -- > Best Regards, > Yuval Itzchakov. >
