go
create proc pro_tracy
@P1 int
as
if @P1=1
begin
Select a, b, c from table1 order by a
end
if @P1=2
begin
Select a, b, c from table1 order by b
end
if @P1=3
begin
Select a, b, c from table1 order by c
end

------解决方案--------------------
还可以使用order by case  when @P1=1 then a when @P1=2 then b when @P1=3 then c end