delete-duplicate-emails

java

python

python3

mysql

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csharp

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swift

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racket

erlang

elixir

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cangjie

Database

Table: <code>Person</code>

<pre>
+-------------+---------+
| Column Name | Type |
+-------------+---------+
| id | int |
| email | varchar |
+-------------+---------+
id is the primary key (column with unique values) for this table.
Each row of this table contains an email. The emails will not contain uppercase letters.
</pre>

&nbsp;

Write a solution to delete all duplicate emails, keeping only one unique email with the smallest <code>id</code>.

For SQL users, please note that you are supposed to write a <code>DELETE</code> statement and not a <code>SELECT</code> one.

For Pandas users, please note that you are supposed to modify <code>Person</code> in place.

After running your script, the answer shown is the <code>Person</code> table. The driver will first compile and run your piece of code and then show the <code>Person</code> table. The final order of the <code>Person</code> table does not matter.

The result format is in the following example.

&nbsp;
Example 1:

<pre>
Input: 
Person table:
+----+------------------+
| id | email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
| 3 | john@example.com |
+----+------------------+
Output: 
+----+------------------+
| id | email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
+----+------------------+
Explanation: john@example.com is repeated two times. We keep the row with the smallest Id = 1.
</pre>

delete_duplicate_emails

Delete Duplicate Emails

表:&nbsp;<code>Person</code>

<pre>
+-------------+---------+
| Column Name | Type |
+-------------+---------+
| id | int |
| email | varchar |
+-------------+---------+
id 是该表的主键列(具有唯一值的列)。
该表的每一行包含一封电子邮件。电子邮件将不包含大写字母。
</pre>

&nbsp;

编写解决方案 删除 所有重复的电子邮件，只保留一个具有最小 <code>id</code> 的唯一电子邮件。

（对于 SQL 用户，请注意你应该编写一个 <code>DELETE</code> 语句而不是 <code>SELECT</code> 语句。）

（对于 Pandas 用户，请注意你应该直接修改 <code>Person</code> 表。）

运行脚本后，显示的答案是 <code>Person</code> 表。驱动程序将首先编译并运行您的代码片段，然后再显示 <code>Person</code> 表。<code>Person</code> 表的最终顺序 无关紧要 。

返回结果格式如下示例所示。

&nbsp;

示例 1:

<pre>
输入: 
Person 表:
+----+------------------+
| id | email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
| 3 | john@example.com |
+----+------------------+
输出: 
+----+------------------+
| id | email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
+----+------------------+
解释: john@example.com重复两次。我们保留最小的Id = 1。</pre>