建立DBLINK,来解决!

------解决方案--------------------
两个数据库有建DBLink的话直接更新就好了,update myemp o set o.ename=(select p.ename from myemp@DBLINKNAME  p where o.empid=p.empid and rownum=1) where o.ename is null;
楼主既然这样问没建DBLink的可能性比较大,那就从sdsb2中把myemp的数据全部导出来放到sdsb中的临时表myemp_temp中再更新,update myemp o set o.ename=(select p.ename from myemp_temp p where o.empid=p.empid and rownum=1) where o.ename is null;