Delete 
from A
where id not in (select ID from (select productid,min(id) as ID from A group by productid) T )  
go

Delete  
from b 
where id not in (select iD from A)

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

create table # (id varchar(20),name varchar(20),number varchar(20),productid varchar(20) )

insert into # values('342','162029302','2.4*1217','443')

insert into # values('321','163229302','4.9*1219','443')

insert into # values('765',' price th

------解决方案--------------------
SQL code
delete aa from a aa where exists(select 1 from a where  productid=aa.productid and id>aa.id)
delete b where id not in(select id from a)

------解决方案--------------------
ta上创建触发器


SQL code
CREATE TRIGGER t ON ta
FOR DELETE
AS
    DELETE FROM tb b
    INNER JON DELETED a
        ON a.id=b.id

------解决方案--------------------
---触发器
SQL code

create trigger del_b on 表1
for delete
as
delete from # where id in (select id from deleted)

------解决方案--------------------
delete from b
where  b.id in ( select max(id) from a group by productid having count(1) > 1 )


delete from a
where  a.id in ( select max(id) from a group by productid having count(1) > 1 )