select productid,b.productname,c.productname,lastupdatetime
from product a,productitem b,productitem c
where a.productsubid=b.productsubid
and a.productsubid1=c.productsubid;
from product a,productitem b,productitem c
where a.productsubid=b.productsubid
and a.productsubid1=c.productsubid;
,a.lastupdatetime
from product a
left join productitem b on a.productsubid=b.productsubid
left join productitem c on a.productsubid1=c.productsubid;
from product a,productitem b,productitem c
where a.productsubid=b.productsubid(+)
and a.productsubid1=c.productsubid(+);