During an assessment, a penetration tester obtains access to a Microsoft SQL server using sqlmap...

The command xp_cmdshell executes system-level commands from SQL Server. The command whoami /all is used to enumerate user privileges, group memberships, and security contexts on Windows systems.

From the CompTIA PenTest+ PT0-003 Official Study Guide (Chapter 8 – Post-Exploitation Techniques):

“Using xp_cmdshell and system commands like whoami /all allows testers to identify the privilege level of the database user and system access level.”