Sql-server – How to create a trigger that update the date and time field and modify of the row

It would be fairly easy but I would actually recommend changing the logic of the command that is inserting/updating the data so that it adds the additional information at this point.

However, should you wish to proceed with a trigger you could do something like this:

create trigger my_trigger
on my_table
after insert, update
as
begin
declare @dt datetime = getdate();
update a
set expire_date = CONVERT(DATE, @dt, 101),
    expire_time = CONVERT(TIME, @dt)
from my_table as a
join inserted as b 
on a.product_no = b.product_no; 
end
go  

This uses the INSERTED table to find out the product_no of the rows that have been changed/created. You can find out more about triggers at the link below:

http://msdn.microsoft.com/en-us/library/ms189799.aspx

I hope this helps you.

How about expanding this a little and do a proper log table, logging every update, insert or delete. That way you can keep a proper history. For this, in MySQL, you will need three triggers :

CREATE TABLE EMP ( ID INT,
                   LASTNAME varchar(100),
                   firstname varchar(100),
                   gender varchar(1),
                   dob date,
                   marital varchar(1),
                   ssn varchar(20)
                 );

CREATE TABLE EMPLOG ( empid INT,
                   operation varchar(1),
                   operationdate date,
                   operated_by varchar(200),
                   LASTNAME varchar(100),
                   firstname varchar(100),
                   gender varchar(1),
                   dob date,
                   marital varchar(1),
                   ssn varchar(20)
                 );

CREATE TRIGGER emplog_insert AFTER INSERT ON emp 
FOR EACH ROW 
INSERT INTO emplog VALUES 
(NEW.id,
 'I',
 Now(),
 USER(),
 NEW.lastname,
 NEW.firstname,
 NEW.gender,
 NEW.dob,
 NEW.marital,
 NEW.SSN
);

CREATE TRIGGER emplog_update AFTER UPDATE ON emp 
FOR EACH ROW 
INSERT INTO emplog VALUES 
(NEW.id,
 'U',
 Now(),
 USER(),
 NEW.lastname,
 NEW.firstname,
 NEW.gender,
 NEW.dob,
 NEW.marital,
 NEW.SSN
);

CREATE TRIGGER emplog_delete AFTER DELETE ON emp 
FOR EACH ROW 
INSERT INTO emplog VALUES 
(OLD.id,
 'D',
 Now(),
 USER(),
 OLD.lastname,
 OLD.firstname,
 OLD.gender,
 OLD.dob,
 OLD.marital,
 OLD.SSN
);

If you then wish to check out the history of what happened for a specific employee, you simply run this query :

select *
from Emplog
where empid = ?
order by operationdate