一个查询语句的问题
select     sum(A.mark)    
FROM     A    
where     A.qx_riqi     between     to_date( '2007-8-1 ',     'yyyy-mm-dd ')     and    
                          to_date( '2007-8-30 ',     'yyyy-mm-dd ')    
and     A.id     = '0075 '    
union    
SELECT     SUM(B.piao_mark)    
From         B    
WHERE         B.piao_riqi     between     to_date( '2007-8-1 ',     'yyyy-mm-dd ')     and    
                              to_date( '2007-8-30 ',     'yyyy-mm-dd ')    
and         B.id     = '0075 '    
所得的结果是    
------------    
  sum(A.mark)    
1:   0.1
2:   0.9
--------
实际上我想要的结果是
      sum(A.mark)     sum(b.mark)
1:     0.1                         0.9
请问怎样修改这个sql语句呢？两个select语句的时间参数，和id是一样的

------解决方案--------------------
这样写就可以了

select *
from (select sum(A.mark)
FROM A
where A.qx_riqi between to_date( '2007-8-1 ', 'yyyy-mm-dd ') and
to_date( '2007-8-30 ', 'yyyy-mm-dd ')
and A.id = '0075 '),
(SELECT SUM(B.piao_mark)
From B
WHERE B.piao_riqi between to_date( '2007-8-1 ', 'yyyy-mm-dd ') and
to_date( '2007-8-30 ', 'yyyy-mm-dd ')
and B.id = '0075 ');