Hey Siva,
Can you try adding the following to your table's configuration:
'value.fields-include' = 'EXCEPT_KEY'
Best,
--Gunnar
On Wed, 28 May 2025 at 20:52, Siva Ram Gujju <sivaram2...@gmail.com> wrote:
> Hello,
>
> I am new to Flink. Running into an issue to read Key from Kafka messages
> in Flink SQL Client.
>
> I have an Order Kafka topic with below messages:
>
> Key: {"orderNumber":"1234"}
> Value: {"orderDate":"20250528","productId":"Product123"}
>
> I am able to get the key and value by using
>
> kafka-console-consumer.bat --property "print.key=true" --topic Orders
> --from-beginning --bootstrap-server xxxxxx
>
>
> I tried to create a table in Flink SQL:
>
> CREATE TABLE Orders (
> orderNumber STRING,
> orderDate STRING,
> productId STRING
> ) WITH (
> 'connector' = 'kafka',
> 'topic' = 'Orders',
> 'properties.bootstrap.servers' = 'xxxxxx',
> 'properties.group.id' = 'FlinkGroupId',
> 'format' = 'json',
> 'scan.startup.mode' = 'earliest-offset',
> 'key.format' = 'json',
> 'key.fields' = 'orderNumber;'
> );When I query the table select * from Orders; orderNumber is printing as
> "NULL" instead of the actual orderNumber.
>
>
> - I tried changing the type to string. Still it is printing as "NULL"
> - If I send a malformed JSON in the key, Flink is throwing an error.
> So, it is clear that Flink is trying to parse the key field as JSON. But
> why is it printing as "NULL" in the select query output?
>
>
> Can anyone please advise what I am doing wrong?
>
> Thanks,
> Siva
>
