USE master
GO
CREATE TRIGGER connection_limit_trigger ON ALL SERVER
    WITH EXECUTE AS 'logon_trigger_login'
    FOR LOGON
AS
BEGIN
    DECLARE @original_login SYSNAME = ORIGINAL_LOGIN();
    
    -- the list of logins to restrict
    IF (
        SELECT  NUM_ALLOWED
        FROM    GK50LIVE.dbo.LimitedLogins
        WHERE   LOGIN_ID = @original_login
       ) < (
            SELECT  COUNT(*)
            FROM    sys.dm_exec_sessions
            WHERE   is_user_process = 1
                    AND original_login_name = @original_login
           ) 
        BEGIN
            ROLLBACK
        END
END;
GO

SELECT ORIGINAL_LOGIN()

SELECT ORIGINAL_LOGIN

Use master
go
-- create the logon trigger
CREATE TRIGGER connection_limit_trigger ON ALL SERVER
    WITH EXECUTE AS 'logon_trigger_login'
    FOR LOGON
AS
BEGIN
	-- the list of logins to restrict
    IF (
        SELECT  NUM_ALLOWED
        FROM    GK50LIVE.dbo.LimitedLogins
        WHERE   LOGIN_ID = ORIGINAL_LOGIN()
       ) < (
            SELECT  COUNT(*)
            FROM    sys.dm_exec_sessions
            WHERE   is_user_process = 1
                    AND original_login_name = ORIGINAL_LOGIN()
           ) 
        BEGIN
            ROLLBACK
        END
END;
GO

ELSE
    COMMIT
END

USE GK50LIVE;
GO
CREATE USER [logon_trigger_login] FROM LOGIN [logon_trigger_login] WITH DEFAULT_SCHEMA = [dbo];
GO
GRANT SELECT ON dbo.LimitedLogins TO logon_trigger_login;
GO

USE master;
GO
GRANT VIEW SERVER STATE TO logon_trigger_login;
GO