update t1 set t1.instancecount=t2.instancecount from TT_V_T_2 t1,tt_v_t2 t2 where t1.ActivityName = t2.ActivityName

update t1 
set instancecount=
(select t2.instancecount 
from TT_V_T_2 t1,tt_v_t2 t2 
where t1.ActivityName = t2.ActivityName)

------解决方案--------------------

+1  非常正解，用标准SQL的话。
探讨


SQL code

update t1 
set instancecount=
(select t2.instancecount 
from TT_V_T_2 t1,tt_v_t2 t2 
where t1.ActivityName = t2.ActivityName)


------解决方案--------------------
用另外一种方式进行。。。

------解决方案--------------------
采用select 和update

update
(
里面是关联的SQL
)

------解决方案--------------------
楼主的方法不可行么？
1楼的法子，前两天在ACCESS里用到了。。

------解决方案--------------------
探讨

SQL code

update t1 
set instancecount=
(select t2.instancecount 
from TT_V_T_2 t1,tt_v_t2 t2 
where t1.ActivityName = t2.ActivityName)