if objectid('f_name') is not null
drop function f_name
go
create function f_name(f_id integer)
returns varchar(1000)
as
BEGIN
DECLARE @class VARCHAR(8000)
SELECT @class=''
SELECT @class=@class+','+f_classname FROM t_chooseclass WHERE f_id=@f_id
SELECT @class=RIGHT(@class,LEN(@class)-1)
RETURN @class
END
go