# Write your MySQL query statement below
183. 从不订购的客户
某网站包含两个表，Customers 表和 Orders 表。编写一个 SQL 查询，找出所有从不订购任何东西的客户。
Customers 表：
+----+-------+ | Id | Name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | +----+-------+
Orders 表：
+----+------------+ | Id | CustomerId | +----+------------+ | 1 | 3 | | 2 | 1 | +----+------------+
例如给定上述表格，你的查询应返回：
+-----------+ | Customers | +-----------+ | Henry | | Max | +-----------+
原站题解
mysql 解法, 执行用时: 539 ms, 内存消耗: 0 B, 提交时间: 2022-05-29 13:48:02
# Write your MySQL query statement below select Name as Customers from Customers where Id not in (select CustomerId from Orders);
pythondata 解法, 执行用时: 308 ms, 内存消耗: 60 MB, 提交时间: 2023-08-07 16:32:20
import pandas as pd
def find_customers(customers: pd.DataFrame, orders: pd.DataFrame) -> pd.DataFrame:
# 选择 orders['customerId'] 中 'id' 不存在的行。
df = customers[~customers['id'].isin(orders['customerId'])]
# 创建一个只包含 name 列的数据框架
# 并将列 name 重命名为 Customers。
df = df[['name']].rename(columns={'name': 'Customers'})
return df
mysql 解法, 执行用时: 546 ms, 内存消耗: 0 B, 提交时间: 2022-08-01 11:20:41
# Write your MySQL query statement below select Name as Customers from Customers where id not in (select distinct CustomerId from Orders);