update 表2
set partspri =表1.jiage
from 表1
where 表1.bianma = 表2.partsnum

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

create table #a (bianma varchar(20),jiage int )
create table #b(Partsnum varchar(20),Partspri int)
--drop table #b
--drop table #a
insert into #a select '111AADDD',111 UNION ALL
select '222ffg',21 UNION ALL
select '3434ffggg',34
insert into #b select '111AADDD',0 UNION ALL
select '1222dfdf',0 UNION ALL
select '2d232323',0
select * from #a
select * from #b
update b set b.Partspri=a.jiage from #a a,#b b where a.bianma=b.partsnum
--结果：
Partsnum   Partspri
111AADDD    111
1222dfdf    0
2d232323    0