183. Customers Who Never Order - 从不订购的客户 <easy>

本文介绍如何使用SQL查询找出从未下单的客户。通过一个具体的例子展示了如何从Customers表中筛选出那些Id不在Orders表中的记录。

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       |
+-----------+

Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything.

select Name as `Customers`
from Customers 
where Id not in (select CustomerId from Orders)

 

运行结果的http://127.0.0.1:5000/网页代码: <!-- templates/dashboard.html --> <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Olist Customers Data Dashboard</title> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css"> <link rel="stylesheet" href="/static/styles.css"> <script src="https://cdn.jsdelivr.net/npm/echarts/dist/echarts.min.js"></script> </head> <body> <div class="container"> <h1 class="text-center mt-5">Olist Customers Data Dashboard</h1> <!-- Dropdown for State Selection --> <div class="row justify-content-center mt-5"> <div class="col-md-4"> <select id="state-dropdown" class="custom-select"> <option value="all">All States</option> </select> </div> </div> <!-- Charts Section --> <div class="row mt-5"> <div class="col-md-6"> <div id="graph1" class="chart-container"></div> </div> <div class="col-md-6"> <div id="graph2" class="chart-container"></div> </div> </div> <div class="row mt-5"> <div class="col-md-6"> <div id="graph3" class="chart-container"></div> </div> <div class="col-md-6"> <div id="graph4" class="chart-container"></div> </div> </div> <div class="row mt-5"> <div class="col-md-6"> <div id="graph5" class="chart-container"></div> </div> <div class="col-md-6"> <div id="graph6" class="chart-container"></div> </div> </div> </div> <script src="https://code.jquery.com/jquery-3.5.1.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/@popperjs/core@2.9.3/dist/umd/popper.min.js"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script> <script src="/static/dashboard.js"></script> </body> </html> 没有东西显示
最新发布
06-18
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