selecet a+b as [列1]，c/d as[列2] from 表1

create table m_name  (id int,name varchar(4))
insert into m_name
select 1,'张三' union all
select 2,'李四' union all
select 3,'王五'

select * from m_name
/*
id          name
----------- ----
1           张三
2           李四
3           王五
*/

create table m_chengji  (name varchar(4),kemu int,chengji int,id sql_variant)
insert into m_chengji
select '张三',1,95,null union all
select '张三',2,92,null union all
select '张三',3,91,null union all
select '李四',1,56,null union all
select '李四',2,76,null union all
select '李四',3,99,null union all
select '王五',1,57,null union all
select '王五',2,100,null union all
select '王五',3,67,null

select * from m_chengji
/*
name kemu        chengji     id
---- ----------- ----------- -----------
张三   1           95          NULL
张三   2           92          NULL
张三   3           91          NULL
李四   1           56          NULL
李四   2           76          NULL
李四   3           99          NULL
王五   1           57          NULL
王五   2           100         NULL
王五   3           67          NULL
*/

update m_chengji 
set id = a.id from m_chengji b left join m_name a on a.[name]=b.[name]