Microsoft SQL - Add an auto update clause to a column (MSSQL)

MSSQL_add_auto_update.sql

create table testing
(
	id int primary key clustered,
	value varchar(50) not null,
	updated_at datetime2 
);

insert into testing values
(1, 'foo', null),
(2, 'bar', null);

select * from testing;

CREATE TRIGGER tgr_updated_at
on testing
after update as
	update testing
	set updated_at = GETDATE()
	where id in (select id from inserted);

select * from testing;

update testing set value = 'biz' where id = 1;

select * from testing;

drop trigger tgr_updated_at;
drop table testing;