Update 更新语句使用两个表关联
=============错误例子=======================================
update tcodeLocation
set plocationid = p.LocationID
from TcodeLocation t , tcodelocation p where p.locationcode=t.plocationcode
and t.locationlevel>1
=============正确=======================================
update t --- (使用别名)
set plocationid = p.LocationID
from TcodeLocation t , tcodelocation p where p.locationcode=t.plocationcode
and t.locationlevel>1