mirror of
https://gitee.com/coder-xiaomo/leetcode-problemset
synced 2025-11-04 03:33:12 +08:00
67 lines
1.4 KiB
HTML
67 lines
1.4 KiB
HTML
<p>Table: <code>Customers</code></p>
|
|
|
|
<pre>
|
|
+-------------+---------+
|
|
| Column Name | Type |
|
|
+-------------+---------+
|
|
| id | int |
|
|
| name | varchar |
|
|
+-------------+---------+
|
|
id is the primary key (column with unique values) for this table.
|
|
Each row of this table indicates the ID and name of a customer.
|
|
</pre>
|
|
|
|
<p> </p>
|
|
|
|
<p>Table: <code>Orders</code></p>
|
|
|
|
<pre>
|
|
+-------------+------+
|
|
| Column Name | Type |
|
|
+-------------+------+
|
|
| id | int |
|
|
| customerId | int |
|
|
+-------------+------+
|
|
id is the primary key (column with unique values) for this table.
|
|
customerId is a foreign key (reference columns) of the ID from the Customers table.
|
|
Each row of this table indicates the ID of an order and the ID of the customer who ordered it.
|
|
</pre>
|
|
|
|
<p> </p>
|
|
|
|
<p>Write a solution to find all customers who never order anything.</p>
|
|
|
|
<p>Return the result table in <strong>any order</strong>.</p>
|
|
|
|
<p>The result format is in the following example.</p>
|
|
|
|
<p> </p>
|
|
<p><strong class="example">Example 1:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong>
|
|
Customers table:
|
|
+----+-------+
|
|
| id | name |
|
|
+----+-------+
|
|
| 1 | Joe |
|
|
| 2 | Henry |
|
|
| 3 | Sam |
|
|
| 4 | Max |
|
|
+----+-------+
|
|
Orders table:
|
|
+----+------------+
|
|
| id | customerId |
|
|
+----+------------+
|
|
| 1 | 3 |
|
|
| 2 | 1 |
|
|
+----+------------+
|
|
<strong>Output:</strong>
|
|
+-----------+
|
|
| Customers |
|
|
+-----------+
|
|
| Henry |
|
|
| Max |
|
|
+-----------+
|
|
</pre>
|