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Deven
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64 lines
1.8 KiB
Markdown
<h2><a href="https://leetcode.com/problems/customers-who-never-order/">183. Customers Who Never Order</a></h2><h3>Easy</h3><hr><div class="sql-schema-wrapper__3VBi"><a class="sql-schema-link__3cEg">SQL Schema<svg viewBox="0 0 24 24" width="1em" height="1em" class="icon__1Md2"><path fill-rule="evenodd" d="M10 6L8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"></path></svg></a></div><div><p>Table: <code>Customers</code></p>
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<pre>+-------------+---------+
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| Column Name | Type |
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+-------------+---------+
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| id | int |
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| name | varchar |
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+-------------+---------+
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id is the primary key column for this table.
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Each row of this table indicates the ID and name of a customer.
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</pre>
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<p> </p>
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<p>Table: <code>Orders</code></p>
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<pre>+-------------+------+
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| Column Name | Type |
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+-------------+------+
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| id | int |
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| customerId | int |
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+-------------+------+
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id is the primary key column for this table.
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customerId is a foreign key of the ID from the Customers table.
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Each row of this table indicates the ID of an order and the ID of the customer who ordered it.
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</pre>
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<p> </p>
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<p>Write an SQL query to report all customers who never order anything.</p>
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<p>Return the result table in <strong>any order</strong>.</p>
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<p>The query result format is in the following example.</p>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<pre><strong>Input:</strong>
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Customers table:
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+----+-------+
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| id | name |
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+----+-------+
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| 1 | Joe |
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| 2 | Henry |
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| 3 | Sam |
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| 4 | Max |
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+----+-------+
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Orders table:
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+----+------------+
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| id | customerId |
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+----+------------+
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| 1 | 3 |
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| 2 | 1 |
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+----+------------+
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<strong>Output:</strong>
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+-----------+
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| Customers |
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+-----------+
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| Henry |
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| Max |
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+-----------+
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</pre>
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</div> |