最小公约数

Create FUNCTION [dbo].[GetMaxgongyue]
(
	@num1   int ,
	@num2  int 
)
RETURNS  int
as 
begin
DECLARE @times INT 
DECLARE @min INT 
DECLARE @result BIGINT 

IF( @num1 >= @num2 ) 
  SET @min=@num2 
ELSE 
  SET @min=@num1 

SET @times=@min 

WHILE(@times <= @min ) 
  BEGIN 
      IF( @num1%@times = 0 
          AND @num2%@times = 0 ) 
        BEGIN 
            SET @result=@times 

            BREAK 
        END 

      SET @times=@times - 1 
  END 

return @result
end

drop table tt
Create table tt(t1  int,t2  int)
insert into  tt(t1 ,t2 )values(1,3)
insert into  tt(t1 ,t2 )values(2,4)
insert into  tt(t1 ,t2 )values(3,9)
insert into  tt(t1 ,t2 )values(6,3)
insert into  tt(t1 ,t2 )values(4,2)
insert into  tt(t1 ,t2 )values(2,331)
select t1,t2,t1%t2 取余,
case when t1%t2<>0 and dbo.GetMaxgongyue(t1,t2)=1 then CAST(t1 as NCHAR(4))+'/'+ CAST(t2 as NCHAR(4)) 
     when t1%t2<>0 and dbo.GetMaxgongyue(t1,t2)<>1 then CAST(t1/dbo.GetMaxgongyue(t1,t2) as NCHAR(4))+'/'+ CAST(t2/dbo.GetMaxgongyue(t1,t2) as NCHAR(4)) 
else cast(cast(t1/t2 as decimal(9,5)) as NCHAR(20)) end result
from tt