permission

Specifies a permission that can be granted on a SQL Server login. For a list of the permissions, see the Remarks section later in this topic.

LOGIN :: SQL_Server_login

Specifies the SQL Server login on which the permission is being granted. The scope qualifier (::) is required.

SERVER ROLE :: server_role

Specifies the user-defined server role on which the permission is being granted. The scope qualifier (::) is required.

TO <server_principal>

Specifies the SQL Server login or server role to which the permission is being granted.

SQL_Server_login

Specifies the name of a SQL Server login.

SQL_Server_login_from_Windows_login

Specifies the name of a SQL Server login created from a Windows login.

SQL_Server_login_from_certificate

Specifies the name of a SQL Server login mapped to a certificate.

SQL_Server_login_from_AsymKey

Specifies the name of a SQL Server login mapped to an asymmetric key.

server_role

Specifies the name of a user-defined server role.

WITH GRANT OPTION

Indicates that the principal will also be given the ability to grant the specified permission to other principals.

AS SQL_Server_login

Specifies the SQL Server login from which the principal executing this query derives its right to grant the permission.

Permissions at the server scope can be granted only when the current database is master.

Information about server permissions is visible in the sys.server_permissions catalog view. Information about server principals is visible in the sys.server_principals catalog view.

SQL Server logins and server roles are server-level securables. The most specific and limited permissions that can be granted on a SQL Server login or server role are listed in the following table, together with the more general permissions that include them by implication.

For logins, requires CONTROL permission on the login or ALTER ANY LOGIN permission on the server.

For server roles, requires CONTROL permission on the server role or ALTER ANY SERVER ROLE permission on the server.

A. Granting IMPERSONATE permission on a login

USE master;
GRANT IMPERSONATE ON LOGIN::WanidaBenshoof to [AdvWorks\YoonM];
GO

B. Granting VIEW DEFINITION permission with GRANT OPTION

USE master;
GRANT VIEW DEFINITION ON LOGIN::EricKurjan TO RMeyyappan 
    WITH GRANT OPTION;
GO 

C. Granting VIEW DEFINITION permission on a server role

USE master;
GRANT VIEW DEFINITION ON SERVER ROLE::Sales TO Auditors ;
GO 

Reference

Concepts