再问个SQL的update 问题

[clubsondy]

如果我想将一个表中的某些字段的数据更新到另一个表，以关健字pd_ID为相关联，又怎样写SQL呢？

例如： A表： pd_ID name expression

1 test1 abc
2 test2 asdf
3 test3 zxcv


B表： pd_ID name expression

1 test1 qwer
2 test2 lkjh
3 test3 piuu
4 test4 uopp

我想将A表中的expression字段与B表中相关联的更新，只是更新A表中有记录的数据。

[playwarcraft]

update A set A.expression=B.expression from B where A.pd_ID=B.pd_ID

[waterfirer]

update b set expression=(select expression from a where a.pd_ID=b.pd_ID) where exists(select 1 from a where a.pd_ID=b.pd_ID)

[clubsondy]

如果要更新几个字段呢？比如有：expression,expression1,expression2.
是不是：update A set A.expression=B.expression，A.expression1=B.expression1,A.expression2=B.expression2 from B where A.pd_ID=B.pd_ID
这可以了呢？

或者是waterfirer(水清)的写法：
update b set expression=(select expression from a where a.pd_ID=b.pd_ID)，expression1=(select expression1 from a where a.pd_ID=b.pd_ID) where exists(select 1 from a where a.pd_ID=b.pd_ID)呢？

[dba_sunny]

update A
set A.expression=B.expression
from A,B
where A.pd_ID=B.pd_ID and A.name=B.name

[九斤半]

create table A(pd_ID int,name varchar(10),expression varchar(10))
insert A
select 1,'test1','abc' union all
select 2,'test2','asdf' union all
select 3,'test3','zxcv'
select * from A

create table B(pd_ID int,name varchar(10),expression varchar(10))
insert B
select 1,'test1','qwer' union all
select 2,'test2','lkjh' union all
select 3,'test3','piuu' union all
select 4,'test4','uopp'
select * from B

begin tran
update A set A.name=B.name,A.expression=B.expression
from A,B where A.pd_ID=B.pd_ID and A.name=B.name

--update A set name=(select name from B where pd_ID=A.pd_ID),
--expression=(select expression from B where pd_ID=A.pd_ID)

select * from A
rollback tran

drop table A,B

[clubsondy]

谢谢，先用playwarcraft的方法解决了，后面的方法会再试试，谢谢大家了。

[clubsondy]

结贴。