Search notes:

SQL Server function: is_member

is_member checks if the current user is member of a Windows group or a SQL Server database role. It returns 0, 1 or null.

Checking for membership in a Windows group.

select is_member('DOMN\GRP')
select is_member('NT AUTHORITY\SYSTEM')

Checking for membership in a database role:

select is_member('db_datawriter')

The following returns null because sysadmin is a server role, not a database role:

select is_member('sysadmin')

See also