sql 关联表update

 

 

update customers a 
set city_name=(select b.city_name from tmp_cust_city b where b.customer_id=a.customer_id)
where exists (select 1 
from tmp_cust_city b
where b.customer_id=a.customer_id
)

 

 

 update 超过2个值：

update customers a 
set (city_name,customer_type)=(select b.city_name,b.customer_type 
from tmp_cust_city b 
where b.customer_id=a.customer_id)
where exists (select 1 
from tmp_cust_city b
where b.customer_id=a.customer_id
)