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.
