sql join query copying its own values when it should be null

See more:

SQL-Server

SQL-Server-2008

hi please help in a sql query...
join on two table the structure is as follows

table 1

name       amt          month       year         id   
H12	1453098.00	  9	    2010	1458
H12	25739446.00	 10	    2010	1458

table 2

name       namt         month       year         id
H11	7600518.00	 10	    2010	1465
H12	239937.00	 10	    2010	1458

i wrote a join query :

select distinct t1.amt ,t2.namt, t1. id,t1.month from 
table1 t1 left outer join table2 t2 on t1.name=t2.name and t1.id=t2.id
it is resulting the rows 

amt                    namt            id       month
1453098.00	   239937.00	     1458	9
25739446.00	   239937.00	     1458	10

whereas the result should be
amt namt id month
1453098.00 null 1458 9
25739446.00 239937.00 1458 10
i.e the namt value for month 9 should be null
,pls correct the query