When using the SAP-supplied method for a system copy, often you will find yourself in the situation that you cannot install the permanent license key for the target system since the information from the source system is stored in the database already. The SAP-recommended remedy for this is to delete the invalid license keys before proceeding with the new key install. Of course, it is not as easy as that for a few reasons:
1. If you do not have at least a temporary license installed, you must log in as user SAP*, which does not have the authorization to delete license keys.
2. If you do have a temporary license installed, and you are logged in as a user with authorization to delete license keys, you still cannot delete the invalid licenses because the delete step validates the key to be deleted with the system information. And guess what? They don’t match , so you cannot delete the key.
This brings us to the real solution, which took a little digging inside the SAP Marketplace to find: You must manually remove the invalid keys from the database. That’s it! Just remove the entries from table SAPLIKEY and all your troubles will be over. Well, at least you will be able to install the new license with the correct information.
Life 
I am not a programmer but I have this SQL subject this session and have to prepare for it. What all topics should be covered in it?
And has anyone studied from this course http://www.wiziq.com/course/125-comprehensive-introduction-to-sql of SQL tutorial online?? or tell me any other guidance…
would really appreciate help
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