This is a free official forum.
If you encounter problems in the process of using or learning SQL, you can ask questions on it, and someone will answer them.
If you need a SQL learning documentation, then I would recommend the official documentation.
https://learn.microsoft.com/en-us/sql/sql-server/?view=sql-server-ver16
If you need to find a mentor, I am afraid I cannot help you.
Best regards,
Percy Tang