向大家请教一个SQL(2)

Question

现有两张表T1  ,T2T1
eventid        eventcount1
10003          240000
40001          230000
30001          220000
20007          210000
70002          121000
T2
eventid        eventcount2
20007          210000
30010          130000
70002          100000现我要得出下面的结果
eventid     eventcount1       eventcount2
10003       240000               0
40001       230000               0
30001       220000               0
20007       210000               0
70002       121000               0
30010        0                   13000请问ＳＱＬ　怎么写　　谢谢        

Answer 1

难道没有规律可循？
SELECT A.EVENTID,NVL(T1.EVENTCOUNT1,0) EVENTCOUNT1, NVL(T2.EVENTCOUNT2,0)
FROM
(SELECT eventid  FROM T1 UNION SELECT EVENTID FROM T2) A LEFT JOIN T1 ON A.EVENTID=T1.EVENTID LEFT JOIN T2 ON A.EVENTID=T2.EVENTID)        

Answer 2

select a..eventid,nvl(b.eventcount1,0) eventcount1,nvl(c.eventcount2,0) eventcount2
from 
(select eventid from t1 union select eventid from t2)a
left join t1 b on a.eventid=b.eventid
left join t2 c on a.eventid=c.eventid

Answer 3

select t1.eventid,t1.eventcount1,nvl(t2.eventcount2,0)
from t1,t2
where t1.eventid=t2.eventid(+)
union
select t2.eventid,nvl(t1.eventcount,0),t2.eventcount2
from t1,t2
where t1.eventid(+)=t2.eventid

Answer 4

select t.eventid,
nvl(t1.eventcount1,0) eventcount1,
decode(nvl(t1.eventcount1,0), 0,nvl(t2.eventcount2,0), 0) eventcount2 
from 
(select eventid from t1 union select eventid from t2)t,t1,t2
where t.eventid=t1.eventid(+) and t.eventid=t2.eventid(+)

Answer 5

select eventid  , eventcount1 , 0 eventcount2 from T1
union all
select eventid  , 0 eventcount1 , eventcount2 from T2 WHERE T2.eventid NOT IN (SELECT eventid  FROM T1) ;