[hotfix][docs] Add Kafka-to-Kafka SQL example to documentation

[Ashfaqbs]

What is the purpose of the change

This is a documentation-only change, submitted as a [hotfix][docs] per contribution guidelines.

It adds an example demonstrating how to use Apache Flink SQL to build an end-to-end streaming pipeline using Kafka as both the source and the sink.

The example illustrates:

• Defining input and output Kafka tables using Flink SQL.
• Writing a transformation query that filters and modifies the stream.
• Setting up Kafka topics and verifying the results.
• Viewing the job graph in the Flink UI.

Brief change log

• Added kafka-to-kafka.md under docs/content/docs/dev/table/sql/examples/
• Includes sample SQL statements, Kafka commands, and notes for verifying output.

Does this pull request potentially affect one of the following parts:

• Dependencies: No
• The public API: No
• The documentation: Yes
• The build system: No
• The runtime per-job behavior: No

Documentation

Adds a new SQL usage example under: docs/dev/table/sql/examples/kafka-to-kafka.md

[flinkbot]

CI report:

• 8bac1bd22835eb72831af3dbe3e7afa240ab46f2 Azure: FAILURE

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[Ashfaqbs]

https://medium.com/@ashfaqbs/real-time-kafka-to-kafka-stream-processing-with-apache-flink-sql-c534a1d67501

[Ashfaqbs]

Thanks again @davidradl for the detailed review — I’ve addressed all feedback in the latest commit and replied to each comment inline.

[davidradl]

@Ashfaqbs Please could you follow https://flink.apache.org/how-to-contribute/contribute-code/ and start the tile of the PR with either [Jira number] or [hotfix].

[Ashfaqbs]

@davidradl, Updated PR title to [hotfix][docs] … and clarified in the description that this is a documentation-only change per the contribution guidelines.

[davidradl]

I suggest raising this on the dev list and then have a Jira as per the process . Otherwise you will have done a lot of work to find it will not get merged, you will need to get buy-in from the committers.