T-SQL编写程序，将十进制数值转换为二进制字符串后输出

declare @ch nchar(10),@n int,@a int
set @n=20
set @ch=''
print cast(@n as varchar(5))+'的二进制为：'
while @n<>0
begin
	set @a=@n%2
	set @n=@n/2
	set @ch=char(48+@a)+@ch
end
print @chdeclare @ch nchar(10),@n int,@a int
set @n=20
s