isnull function in sql server

Replaces NULL with the specified replacement value.

Syntax :

ISNULL ( check_expression , replacement_value )

Example  :

                    If any Parameter has null value ,you can replace with specified value.

                  

-------------------CREATE Table --------------

create table testtable

(

  amount int null

)

---------------------Now inset null value in table------------------

insert into testtable

select null

--------------This table now return null value--------------------

select amount from testtable

-----------Output

---  NULL

--------------Now using ISNULL function-replace Null value to 0---------------

select isnull(amount,0)

-------------------After Using ISNULL function output is  0

drop table testtable