Hi @Sarvesh Pandey ,
Thankyou for using Microsoft Q&A platform and thanks for posting your question here.
As I understand your issue, you are trying to use join transformation in mapping dataflow, however, it is not working as expected. Please let me know if my understanding is incorrect .
Kindly make sure the schema has been imported correctly for both the source datasets that you are trying to join . Try importing projection in the source dataset too and check if it works for you.
In order to provide you better help, Could you please share the screenshot of the join transformation configurations to know what is missing at your end. Also, kindly let us know what are the two source datasets in your case for joining. Looking forward to your response. Thanks !