Hi Vincent,
I'm not well into Flink SQL, so I'm pulling in Jark.
I have stopped using union records in your way and instead only use
nullable fields (technically also a union field but much easier to handle
in all languages).
So if you have a way to change the schema, maybe try it out:
record RowEvent {
union { null, ItemRow } item_row default null;
union { null, RefundRow } refund_row default null;
}
On Thu, Mar 18, 2021 at 7:35 AM Vincent Dong <dyb0...@163.com> wrote:
> Hi All,
> How does Flink SQL read Kafka Avro message which has union field?
> For me, avro schema is defined as following,
> ```
> record ItemRow {
> string num_iid;
> string has_showcase;
> string jdp_created;
> }
>
> record RefundRow {
> string refund_id;
> string status;
> string jdp_created;
> }
>
> record RowEvent {
> union { ItemRow, RefundRow } item_row;
> }
> ```
> Now I'm sure that for a specific kafka topic, the item_row in all messages
> is RefundRow, but I don't know how to define source table and query the
> table.
> Can I define the table to force Flink SQL converts all messages to
> RefundRow? Then I can `select status, refund_id from the_converted_table`.
>
>
> Thanks
> Vincent Dong
>
>
>
>
