select projectid,sum(downloadIncome),sum(adIncome),time 
from (
select projectid,downloadIncome ,0 as adIncome , time from A表
union all
select projectid ,0, adIncome ,time from B表
) t
group by projectid,time
order by time

------解决方案--------------------

SQL code
--还是写一个吧，2楼少关联了一个条件 
 with a as( 
 select 1 projectid, 100 downloadincome, date'2010-04-10' time from dual union all                          
 select 1 projectid, 200 downloadincome, date'2010-04-11' time from dual), 
 b as( 
 select 1 projectid, 100 adincome, date'2010-04-10' time from dual union all                          
 select 1 projectid, 300 adincome, date'2010-04-12' time from dual) 
  
 SELECT nvl(a.projectid, b.projectid) projectid, 
    nvl(a.downloadincome, 0) downloadincome, 
    nvl(b.adincome, 0) adincome, 
    nvl(a.time, b.time) TIME 
 FROM a 
 FULL OUTER JOIN b 
   ON (a.projectid = b.projectid AND a.time = b.time);