假设存在两个表A,B,它们有的字段相同,有的字段不同,如:
A.x1, A.x1, A.a1
B.x1, B.x2, B.b1现在我想把两个表合并起来成C,且C有字段
C.x1, C.x2, C.a1, C.b1要求如果A.x1=B.x1 且 A.x2=B.x2 则该条记录C.a1, C.b1由两表中的数据填充
如果不符合上述要求,则该条记录由其中一表的记录填充,没有的字段设为空
A.x1, A.x1, A.a1
B.x1, B.x2, B.b1现在我想把两个表合并起来成C,且C有字段
C.x1, C.x2, C.a1, C.b1要求如果A.x1=B.x1 且 A.x2=B.x2 则该条记录C.a1, C.b1由两表中的数据填充
如果不符合上述要求,则该条记录由其中一表的记录填充,没有的字段设为空
from A FULL OUTER JOIN B on (A.x1 = B.x1 and A.x2 = B.x2)
select A.x1, A.x2, A.a1, B.b1 from A LEFT OUTER JOIN B on A.x1 = B.x1 and A.x2 = B.x2
select A.x1, A.x2, A.a1, B.b1
from A,B
where A.X1=B.X1(+) and A.X2=B.X2(+)
create table sssyyybbb
as
select a.X1,a.X2,a.A1,b.B1 from shu_aaa a left join shu_bbb b
on a.X1 = b.X1 and a.X2 = b.X2
union
select b.X1,b.X2,a.A1,b.B1 from shu_aaa a right join shu_bbb b
on a.X1 = b.X1 and a.X2 = b.X2