create table a(id int,title varchar(10),addtime datetime)
insert into a values(1,     'aaa',      '2007-02-23') 
insert into a values(2,     'bbb',      '2007-06-05')
create table b(id int,title varchar(10),addtime datetime)
insert into a values(1,     'assf',     '2007-03-23')
insert into a values(2,     'dfsd',     '2007-05-05')
go

select addtime , title from a 
union all 
select addtime , title from b
order by a.addtime desc

drop table a,b


/*
addtime                                                title      
------------------------------------------------------ ---------- 
2007-06-05 00:00:00.000                                bbb
2007-05-05 00:00:00.000                                dfsd
2007-03-23 00:00:00.000                                assf
2007-02-23 00:00:00.000                                aaa

（所影响的行数为 4 行）
*/

------解决方案--------------------
SQL code
select addtime,title from a 
union all 
select addtime,title from b order by addtime desc

------解决方案--------------------
使用 union

------解决方案--------------------
SQL codeselect addtime,title from a  
union all  
select addtime,title from b order by addtime desc