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下面这一段代码一开始死活不出来,后来经过排查原来是(+)在作祟:
select count(*) from
(select pb.Projid,pb.Cityname as city,pb.Regionname as region,pb.Regintypename,pb.townshipname,pb.Projname,
s.addressname as addressname,s.standardid as standardid,s.PROVINCE as province,
s.CITYNAME as cityname,s.REGIONNAME as regionname,s.ROADS as roads
from Projbase pb,Projnameaddressbase pa,Standardaddress s where pb.projid = pa.projid(+)
and pa.standardid=s.standardid(+)
and pb.Currphase = 400 and pb.Ifhb =0and not exists(select m.projid from Projnameaddressbase m where m.projid=pb.projid)
order by pb.Cityid asc,pb.Projname asc)
后来才发现(+)是oracle外连接的运算符,下面总结一下它的用法:
1、该符号可以放在等号的左面,也可以放在等号的右面,但一定要放在缺少信息的那一面;
2、该符号仅适用于列,不能用在表达式上;
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3、该操作符不能与ON和IN操作符一起使用