declare @sdt datetime,@edt datetime
set @sdt='2006-02-03'
set @edt='2008-01-02'

select ltrim(datediff(dd,@sdt,@edt)/365)+'年'+ltrim(datediff(dd,@sdt,@edt)%365/30)+'月'+ltrim(datediff(dd,@sdt,@edt)%365%30)+'天'

create table tb(日期1 datetime,日期2 datetime)
insert into tb select '2006-02-03','2008-01-02'
insert into tb select '2006-06-08','2004-03-05'
insert into tb select '2007-05-06','2008-06-07'

select *,ltrim(datediff(dd,日期1,日期2)/365)+'年'+ltrim(datediff(dd,日期1,日期2)%365/30)+'月'+ltrim(datediff(dd,日期1,日期2)%365%30)+'天' as 间隔
from tb

declare @tb table (d1 datetime,d2 datetime)
insert into @tb
select '2006-02-03','2008-01-02' union all
select '2006-06-08','2004-03-05' union all
select '2007-05-06','2008-06-07'
select d1,d2,cast(datediff(yy,d1,d2) as varchar)+'年'+cast(datediff(mm,d1,d2)/12 as varchar)+'月'+cast(datediff(dd,d1,d2)/12/30 as varchar)+'日' from @tb

--try:

--创建函数
create function f_wsp(@star datetime,@end datetime)
returns varchar(20)
as
begin
    declare @star1 varchar(10),@end1 varchar(10)
    declare @cha varchar(20)
    set @cha=''
    if(@star>=@end)
        set @cha='开始日期大于等于结束日期'
    else
    begin
    set @star1=stuff(convert(varchar(10),@star,120),1,4,'1990')
    set @end1=stuff(convert(varchar(10),@end,120),1,4,'1990')
    if(datediff(dd,@star1,@end1)>0)
    begin
        set @cha=ltrim(datediff(yy,@star,@end))+'年'    
        set @star=stuff(convert(varchar(10),@star,120),1,4,datename(yy,@end))
    end
    else
    begin
        set @cha=ltrim(datediff(yy,@star,@end)-1)+'年'    
        set @star=stuff(convert(varchar(10),@star,120),1,4,ltrim(datepart(yy,@end)-1))
    end
    set @star1=stuff(convert(varchar(10),@star,120),1,7,'1990-01')
    set @end1=stuff(convert(varchar(10),@end,120),1,7,'1990-01')
    if(datediff(dd,@star1,@end1)>0)
    begin
        set @cha=@cha+ltrim(datediff(mm,@star,@end))+'月'    
        set @star=stuff(convert(varchar(10),@star,120),1,7,convert(varchar(7),@end,120))
    end
    else
    begin
        set @cha=@cha+ltrim(datediff(mm,@star,@end)-1)+'月'    
        set @star=stuff(convert(varchar(10),@star,120),1,7,convert(varchar(7),dateadd(mm,-1,@end),120))
    end
    set @cha=@cha+ltrim(datediff(dd,@star,@end))+'天'
    end
    return @cha
end
go


--调用函数：
--> 测试数据: @s
declare @s table (日期1 datetime,日期2 datetime)
insert into @s
select '2006-02-03','2008-01-02' union all
select '2006-06-08','2004-03-05' union all
select '2007-05-06','2008-06-07'

select 日期1,日期2,dbo.f_wsp(日期1,日期2) from @s

create table tb(日期1 datetime,日期2 datetime)
insert into tb select '2006-02-03','2008-01-02'
insert into tb select '2006-06-08','2004-03-05'
insert into tb select '2007-05-06','2008-06-07'
select 相差=Convert(nvarchar,case when datepart(mm,日期2)>datepart(mm,日期1) or datepart(mm,日期2)=datepart(mm,日期1)and datepart(dd,日期2)>=datepart(dd,日期1) then  datepart(yy,日期2)-datepart(yy,日期1) else  datepart(yy,日期2)-datepart(yy,日期1)-1 end)+'年'+ convert(nvarchar,datediff(mm,日期1,日期2)%12)+'月'+Cast(datediff(dd,日期1,日期2)%365%30  as nvarchar)+'日' from tb