Oracle 9i推荐使用ANSI的写法 select A.aa,B.bb,C.cc from A left outer join B on a.aa=b.aa left outer join C on a.aa=c.aa
Oracle: select D.aa, NVL(D.bb,0),NVL(C.cc,0) from (select A.aa, B.bb from A,B where A.aa = B.aa(+)) D,C where D.aa = C.aa(+)
ORACLE: select A.aa, NVL(B.bb,0),NVL(C.cc,0) from A,B,C where A.aa=B.aa(+) and A.aa=C.aa(+)SQL server: select A.aa,isnull(B.bb,0),isnull(C.cc,0) from A left join B on B.aa=A.aa left join C on C.aa=A.aa
--SQL数据库中就应该这样写:select top 100 a.aa,bb=isnull(b.bb,0),cc=isnull(c.cc,0) from a left join b on a.aa=b.aa left join c on a.aa=c.aa
select A.aa,isnull(B.bb,0),isnull(C.cc,0) from A left B on A.aa = B.aa left join C on A.aa = C.aa
select A.aa,B.bb,C.cc from A left outer join B on a.aa=b.aa left outer join C on a.aa=c.aa
select D.aa, NVL(D.bb,0),NVL(C.cc,0)
from
(select A.aa, B.bb from A,B where A.aa = B.aa(+)) D,C
where D.aa = C.aa(+)
select A.aa, NVL(B.bb,0),NVL(C.cc,0)
from A,B,C
where A.aa=B.aa(+)
and A.aa=C.aa(+)SQL server:
select A.aa,isnull(B.bb,0),isnull(C.cc,0)
from A
left join B on B.aa=A.aa
left join C on C.aa=A.aa
from a left join b on a.aa=b.aa
left join c on a.aa=c.aa
left join C on A.aa = C.aa