select a.id,a.name,sum(b.name) ,a.flag
   from a,b
where a.id=b.id
group by a.id,a.name,a.flag

------解决方案--------------------



SQL code
select a.id,a.name,b1.sm,c1.sf  from a 
left join (select id,sum(money) sm from b group by id) b1 
  on b1.id=a.id
left join (select id,decode(sum(flag),0,0,1) sf from c group by id) c1 
  on c1.id=a.id

------解决方案--------------------
TRY IT ..
SQL code
SQL> SELECT A.ID, 
 2     A.NAME, 
 3     SUM(DISTINCT MONEY) "SUM_MONEY", 
 4     MAX(FLAG) "FLAG" 
 5  FROM A, 
 6     B, 
 7     C 
 8   WHERE A.ID = B.ID 
 9   AND B.ID = C.ID 
  10   GROUP BY A.ID,A.NAME 
  11   ; 
  
     ID NAME  SUM_MONEY     FLAG 
 ---------- ---- ---------- ---------- 
      1 AA       80      1 
      2 BB      300      0 
  
 SQL> 


------解决方案--------------------
SQL> select a.*,g.money from (select distinct f.id,sum(f.money*c.flag) over(part
ition by f.id) money from   (select  distinct id,sum(money) over(partition by id
) money from b)  f,c where c.id=f.id) g,a where g.id=a.id;