实现方法二：

CREATE FUNCTION SelectNFromM (@N INT, @M INT)
RETURNS @Temp TABLE (Value NVARCHAR(50),
         MaxIndex INT)
AS
BEGIN
    DECLARE @IndexTemp TABLE ([Index] INT)

    DECLARE @INDEX INT

    SET @INDEX = 0
    WHILE (@INDEX < @M)
    BEGIN
        INSERT @IndexTemp VALUES (@INDEX)
        SET @INDEX = @INDEX + 1
    END

    IF (@N = 1)
    BEGIN
        INSERT @Temp SELECT [Index], [Index] FROM @IndexTemp
    END
    ELSE
    BEGIN
        SET @INDEX = @N - 1;
        INSERT @Temp SELECT a.Value + ' ' + CONVERT(NVARCHAR(50), b.[Index]), b.[Index] FROM SelectNFromM(@INDEX, @M) AS a, @IndexTemp b WHERE b.[Index] > a.MaxIndex
    END

    RETURN
END
GO
SELECT Value FROM SelectNFromM (7, 26)

实现方法三：

create table t (n smallint)

insert t select distinct colid-1 from syscolumns where colid<=26

select t1.n,t2.n,t3.n,t4.n,t5.n,t6.n,t7.n
from t t1,t t2,t t3,t t4,t t5,t t6,t t7
where t1.n<20 and t1.n<t2.n
  and t2.n<21 and t2.n<t3.n
  and t3.n<22 and t3.n<t4.n
  and t4.n<23 and t4.n<t5.n
  and t5.n<24 and t5.n<t6.n
  and t6.n<25 and t6.n<t7.n