oracel merge用法，只贴图不说话
merge into a
using (select i.custid, i.contphonecountry, i.contphonecitycode,i.contphone
from i) b
on (a.custid = b.custid)
when matched then
update
set a.contphone = b.contphonecountry || ' ' || b.contphonecitycode || ' ' ||b.contphone
where a.contphone is not null;