求一句SQL语句

[xiaoyu961121]

select
a.d1,
a.d2,
a.d3,
a.d4,
b.d2, ---
c.d1, ---
a.d5

from

t1 a,
t2 b,
t3 c

where

a.d0 = b.d0 and
a.d6 = c.d6 and
a.d7 = 'XXXXX'
类似一个这样的语句，如果B、C表里没有记录，就查不到数据。但我希望，如果B、C没有记录时，A表的记录仍然显示，B.d2、C.d1用0代替。
（分不够，不好意思）

[yyoinge]

select  
a.d1,
a.d2,
a.d3,
a.d4,
isnull(b.d2, 0) as d2, ---
isnull(c.d1, 0) as d1, ---
a.d5  

from  

t1 a
left join
t2 b
on a.d0 = b.d0
left join
t3 c  
on a.d6 = c.d6 
where   
a.d7 = 'XXXXX'