如何优化一下oracle sql语句，加急！不胜感激
如何优化一下oracle sql语句，加急！不胜感激
select *
from (select i.ID,i.Title,i.ChannelID,i.PublishTime,i.Admin,i.Remark
,i.Reserved1,i.Reserved2,i.CityID,i.TempletID,i.Status,i.Keyword
,i.FileAddress,i.IsPrivate,i.UserGroup,i.IP,i.IsOpen,i.CheckStatus
,i.SubChannelID,i.Click,i.IsTop,i.UpdateTime,i.UserName,i.CityName
,i.PublishTime as PutTime,c.Name,0,''
from P_Information i,P_Channel c
where i.SubChannelID=c.ID and i.ChannelID=1
union all
select i.ID,i.Title,i.ChannelID,i.PublishTime,i.Admin,i.Remark
,i.Reserved1,i.Reserved2,i.CityID,i.TempletID,i.Status,i.Keyword
,i.FileAddress,i.IsPrivate,i.UserGroup,i.IP,i.IsOpen,i.CheckStatus
,i.SubChannelID,i.Click,i.IsTop,i.UpdateTime,i.UserName,i.CityName
,f.OPTime as PutTime,c.Name,f.SubChannelID,rc.Name
from P_Information i,P_InfoReference f,P_Channel c,P_Channel rc
where i.ID=f.InfoID and i.SubChannelID=c.ID and f.SubChannelID=rc.ID
and i.ID in (select i.InfoID
from P_InfoReference i
where 1=1 ) and f.id in(select min(f.id)
from P_Information i,P_InfoReference f
where i.ID=f.InfoID and f.SubChannelID=rc.ID
and i.ID in (select i.InfoID
from P_InfoReference i
where 1=1 ))
)
order by PutTime DESC
