--> 测试数据：@T
declare @表头 table([id] int,[cmaketime] int)
insert @表头
select 1,6 union all
select 1,7 union all
select 1,8 union all
select 2,12 union all
select 2,13 union all
select 2,14 union all
select 3,25 union all
select 3,26 union all
select 3,28

--> 测试数据：@表体
declare @表体 table([id] int,[单价] int)
insert @表体
select 1,3 union all
select 2,5 union all
select 3,6

select 
    *,(select max([cmaketime]) from @表头 where id=t.id) as [cmaketime] 
from @表体 t
/*
id          单价          cmaketime
----------- ----------- -----------
1           3           8
2           5           14
3           6           28
*/