update a
set a.iSafeNum = b.iSafeNum
from bb a join Inventory b on a.cInvCode = b.cInvCode

------解决方案--------------------
update b
set b.iSafeNum = a.iSafeNum
from bb a join Inventory b on a.cInvCode = b.cInvCode



------解决方案--------------------
SQL code
update b
set b.iSafeNum = a.iSafeNum
from bb a join Inventory b on a.cInvCode = b.cInvCode

------解决方案--------------------
SQL code

update Inventory set iSafeNum=bb.iSafeNum 
from Inventory,bb 
where Inventory.cInvCode=bb.cInvCode