I had to connect to a SQL server to provide access to a domain account. Unfortunately, I had no access to the DB/SQL Server. However, I had local admin access to the Windows server thats hosting the SQL. I had to check for the user accounts that had access to the Database instance. I was very fortunate and lucky to connect to the SQL server using psexec with full access. Below listed syntax will help you to login to SQL server.
psexec -i -s “C:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\Ssms.exe”
This helps you to connect to the DB using system account (NT AUTHORITY\SYSTEM). If there is a deny configured to this login. You will not be able to connect.