求一个简单的sql语句 关于两表关联的问题
T1 
 id         name               Date1                              num 
 1            user1            2007-02-01                  3 
 2            user1            2007-02-02                  6 
 3            user2            2007-02-01                  7   
 T2 
 id                  Date2    
 1                     2007-02-01 
 2                     2007-02-02 
 3                     2007-02-03     
 现在我想要两个表关联起来做一个查询 
 (根据T2中的记录)T1中的User1   在2007-02-03这一天没有记录产生,因此我想把查询的结果增加一条   “user1            2007-02-03                  0”   
 查询结果如下:   
 name               Date1                              num 
 user1            2007-02-01                  3 
 user1            2007-02-02                  6 
 user1            2007-02-03                  0 
 user2            2007-02-01                  7 
 user2            2007-02-02                  0 
 user2            2007-02-03                  0   
 谢谢
------解决方案--------------------declare @a table(id int, name  varchar(10),Date1 smalldatetime, num int) 
 insert @a select 1 , 'user1 ',  '2007-02-01 ', 3 
 union all select 2 , 'user1 ',  '2007-02-02 ', 6 
 union all select 3 , 'user2 ',  '2007-02-01 ', 7   
 declare @b table(id int, Date2  smalldatetime) 
 insert @b select 1 , '2007-02-01 ' 
 union all select 2 , '2007-02-02 ' 
 union all select 3 , '2007-02-03 ' 
 union all select 4 , '2007-02-04 '   
 select name,x date,max(num) num 
 from 
 (select name,case when date1=date2 then date1 else date2 end x,num =case when date1=date2 then num else 0 end from @a a , @b b  )aa 
 group by name,x order by name   
------解决方案--------------------select *,isnull((select num from t1 where t1.name=a.name and t1.date1=b.date1),0) as num from (select distinct name from t1) a,(select distinct date2 as date1 from t2) b order by name,date1