Hi,
If you forgot your admin user name and password you can reset the password. To do this, navigate to your Synapse workspace in Azure portal. On Overview blade you will see your SQL admin username, similar to below:
Make a note of username. To reset password, click Reset SQL admin password button at the top:
Enter new password twice and click Save.
NOTE: If Reset SQL admin password button is disabled, it most likely means that only Microsoft Entra ID authentication is supported. To change this, navigate to Settings -- Microsoft Entra ID blade, uncheck Support only Microsoft Entra ID authentication for this workspace and click Save.
Please click Accept Answer and upvote if the above was helpful.
Thanks.
-TP