那些臭名昭著的sql

select * from a, b left join c on b.id = c.id left join d on c.id = d.id

select 
trim(d.circuitid) as circuitid,
trim(d.Code) as Code,
trim(d.Oldname) as Oldname,
trim(d.Circuittype) as Circuittype,
trim(d.Status) as Status,
trim(d.customerid) as acustomerid,
trim(d.alinkman) as alinkman,
trim(d.zlinkman) as zlinkman,
trim(d.alinkmantel) as alinkmantel,
trim(d.zlinkmantel) as zlinkmantel,
trim(d.busi_no) as busi_no,
trim(d.service_serial) as service_serial,
trim(a.region_ID) as regionid ,
2 as SORTID
from test1 a,test2 b,test3 c,test4 d 
where trim(a.room_id)=trim(b.roomID) and trim(b.neid)=trim(c.neid) and (trim(c.portid)=trim(d.aendname) or trim(c.portid)=trim(d.zendname))