update customers a -- 使用别名
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 -- 使用别名
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
)一、随机密码生成。编写程序在26个字母大小写和9个数字组成的列表中随机生成10个8位密码。
import random
def random_password():
list1 = []
#把字母加入序列中
for i in range(65,90):
list1.append(chr(i))
for i in range(97,122):
list1.append(chr(i))
list2 = [1,2,3,4,5,6,7,8,9]
list = list1 +list2
n = 0
while n < 10:
password = []
n = n + 1
m = 0
password = password + random.sample(list, 8)
#把列表转化为字符串
password_middle = [str(i) for i in password]
password_end = ''.join(password_middle)
print("第{}个随机生成的密码是：{}".format(n,password_end))
random_password()
#random.sample(seq, k)实现从序列或集合seq中随机选取k个独立的的元素
#random.randint(a, b) #A-Z:65-90;a-z：97-122;ASCII码48～57为0到9十个阿拉伯数字
