create table tb1(no char(1))
insert into tb1 
 select 1 union select 2 union
 select 3 union select 4 union
 select 5

select * from tb1 
union
select a.no+b.no from tb1 a,tb1 b where a.no>b.no
union
select a.no+b.no+c.no from tb1 a,tb1 b,tb1 c where a.no>b.no and b.no>c.no
union
select a.no+b.no+c.no+d.no from tb1 a,tb1 b,tb1 c,tb1 d where a.no>b.no and b.no>c.no and c.no>d.no
union
select '12345'

/*
no
-----
1
12345
2
21
3
31
32
321
4
41
42
421
43
431
432
4321
5
51
52
521
53
531
532
5321
54
541
542
5421
543
5431
5432

------解决方案--------------------

SQL code
CREATE FUNCTION FN_C(
  @N INT
  ,@R INT
  )
RETURNS INT
AS
BEGIN
IF @N<= 0 
    RETURN 1
DECLARE @RET INT
DECLARE @I INT
SET @I = 1
SET @RET = 1
WHILE @I <= @R 
BEGIN
    SET @RET = @RET * (@N - @I + 1) / @I 
    SET @I = @I + 1
END  
RETURN @RET
END
GO


SELECT DBO.FN_C(5,1)+DBO.FN_C(5,2)+DBO.FN_C(5,3)+DBO.FN_C(5,4)+DBO.FN_C(5,5)

-- 结果
31

------解决方案--------------------

动态的语句懒得写了