假设T1表数据是全的，T2不全

SELECT * FROM T1 ,T2 WHERE T1.A=T2.A(+)

假设两个表都有不全

select * from t1 full join t2 on t1.a=t2.a

假设有三个表可能都不全

select * from t1 full join t2 on t2.a=t1.a full join t3 on t3.a=nvl(t2.a,t1.a)