第一条记录,取省道还是国道有什么规则?如果没有规则,可以随便取的话,这是这样写:select A.id,A.code
,(select name from B where B.id=A.id and rownum<2) as name
,(select flag from B where B.id=A.id and rownum<2) as flag
from A
,(select name from B where B.id=A.id and rownum<2) as name
,(select flag from B where B.id=A.id and rownum<2) as flag
from A
A.id,A.code,B1.name,B1.flag
from
A,B B1
where
A.id=B1.id
and
NOT EXISTS(select * from B where id=A.id and flag<B1.flag)