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请问这个简单的SQL语句怎么写？
第一个表Port结构：
ID(int4) Name
内容 1 SHANGHAI
2 TIANJIN
3 QINGDAO
第二个表Lane结构：
ID(int4) LaneID PortID1 PortID2 PortID3
内容 1 1 1 2 3
现在根据Lane的LaneID值（例如1），返回Port1,Port2,Port3的Name，就是SHANGHAI,TIANJIN,QINGDAO，
请问这个简单的SQL语句怎么写？
ID(int4) Name
内容 1 SHANGHAI
2 TIANJIN
3 QINGDAO
第二个表Lane结构：
ID(int4) LaneID PortID1 PortID2 PortID3
内容 1 1 1 2 3
现在根据Lane的LaneID值（例如1），返回Port1,Port2,Port3的Name，就是SHANGHAI,TIANJIN,QINGDAO，
请问这个简单的SQL语句怎么写？
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ocool 2003-12-16
up
azsoft 2003-12-16
zjcxc(邹建):
select id,lanid
,portname1=(select name from Port where id=a.PortID1)
,portname2=(select name from Port where id=a.PortID2)
,portname3=(select name from Port where id=a.PortID3)
from Lane a
select id,lanid
,portname1=(select name from Port where id=a.PortID1)
,portname2=(select name from Port where id=a.PortID2)
,portname3=(select name from Port where id=a.PortID3)
from Lane a
vileboy 2003-12-15
再改:
select p1.name as port1 ,p2.name as port2,p3.name as port3 from
port as p1 right join
port as p2 right join
port as p3 right join
lane as la
on p3.id=la.protid3
on p2.id=la.protid2
on p1.id=la.protid1
select p1.name as port1 ,p2.name as port2,p3.name as port3 from
port as p1 right join
port as p2 right join
port as p3 right join
lane as la
on p3.id=la.protid3
on p2.id=la.protid2
on p1.id=la.protid1
vileboy 2003-12-15
select p1.name,p2.name,p3.name from
port as p1 right join
port as p2 right join
port as p3 right join
lane as la
on p3.id=la.protid3
on p2.id=la.protid2
on p1.id=la.protid1
zjcxc--个人微信公共号同名 2003-12-15
select id,lanid
,portname1=(select name from Port where id=a.PortID1)
,portname2=(select name from Port where id=a.PortID2)
,portname3=(select name from Port where id=a.PortID3)
from Lane a
yyaoi 2003-12-15
select a.laneid,a.portid1,b.name from lane a,port b
where a.portid1=b.id
union select a.laneid,a.portid2,b.name from lane a,port b
where a.portid2=b.id
union select a.laneid,a.portid3,b.name from lane a,port b
where a.portid3=b.id
where a.portid1=b.id
union select a.laneid,a.portid2,b.name from lane a,port b
where a.portid2=b.id
union select a.laneid,a.portid3,b.name from lane a,port b
where a.portid3=b.id