How to create function

How to create function

CREATE FUNCTION owner_name.function_name ( @parameter_name AS data_type ,...n )
RETURNS data_type
AS
BEGIN
function_body
RETURN value
END


Examples :

CREATE FUNCTION dbo.GetNoWeek (@var Varchar(10))
RETURNS varchar(10)
BEGIN
DECLARE @result varchar(10)
IF @var = 'Ok'
SET @Result = 'Ok'
ELSE
SET @Result = 'Not Ok'
RETURN @Result
END