What is Trigger in SQL Server?

A trigger is a special stored procedure that fires automatically when data modification occurs against a table.

How to Create a Trigger:

Firstly create your table to insert data:

create table tableA
(
id int identity(1,1) primary key,
name varchar(25),
age int check(age>18),
server_date datetime default getdate()
)

Create your second table that affects when trigger fires:

create table tableB
(
id int primary key,
insert_date datetime
)

Now following will be the structure of your trigger for insertion. Here “myfirsttrigger” is the name of the trigger.

create trigger myfirsttrigger on tableA
for insert 
as 
begin
	declare @id int
	select @id=id from inserted
	insert into tableB (id,insert_date) values(@id,getdate());
end