CREATE TRIGGER ModDate
    ON X
    AFTER INSERT, UPDATE
AS
BEGIN

    INSERT INTO X (ModifiedDate)
    VALUES (GETDATE())

END

CREATE TRIGGER ModDate
    ON TableX
    AFTER INSERT, UPDATE
AS
BEGIN
    UPDATE X
    SET ModifiedDate = GETDATE()
    FROM TableX X
    JOIN inserted i ON X.key = i.key -- change to whatever key identifies
                                     -- the tuples
END

CREATE TRIGGER ModDate
ON TableX
AFTER INSERT
AS
BEGIN
UPDATE tableX  SET ModifiedDate = GETDATE() where modifieddate is null
END

create trigger [dbo].[ModDate] on [dbo].[x] after insert,update
as
begin

UPDATE dbo.x
   SET x.ModifiedDate = GETDATE()
  FROM x X
  JOIN inserted I ON X.key = I.key

end