docs(note): 添加题解：196. 删除重复的电子邮箱

zhouboyi1998 · zhouboyi · commit e8230a00a75d · 2025-03-19T18:40:18.000+08:00
diff --git a/markdown/easy/0196.删除重复的电子邮箱.md b/markdown/easy/0196.删除重复的电子邮箱.md
@@ -0,0 +1,155 @@
+<h1 style="text-align: center;"> <span style="color: #00AF9B;">196. 删除重复的电子邮箱</span> </h1>
+
+### 🚀 LeetCode
+
+<base target="_blank">
+
+<span style="color: #00AF9B;">**Easy**</span> [**https://leetcode.cn/problems/delete-duplicate-emails/**](https://leetcode.cn/problems/delete-duplicate-emails/)
+
+---
+
+### ❓ Description
+
+<br/>
+
+**表：** `Person`
+
+```
++-------------+---------+
+| 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.
+```
+
+<br/>
+
+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 `id` 的唯一电子邮件。
+
+（对于 `SQL` 用户，请注意你应该编写一个 `DELETE` 语句而不是 `SELECT` 语句。）
+
+（对于 `Pandas` 用户，请注意你应该直接修改 `Person` 表。）
+
+运行脚本后，显示的答案是 `Person` 表。
+
+驱动程序将首先编译并运行您的代码片段，然后再显示 `Person` 表。
+
+`Person` 表的最终顺序 **无关紧要** 。
+
+返回结果格式如下示例所示。
+
+**示例 1：**
+
+```
+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.
+```
+
+<br/>
+
+**SQL Schema**
+
+```
+Create table If Not Exists Person (Id int, Email varchar(255));
+Truncate table Person;
+insert into Person (id, email) values ('1', 'john@example.com');
+insert into Person (id, email) values ('2', 'bob@example.com');
+insert into Person (id, email) values ('3', 'john@example.com');
+```
+
+<br/>
+
+**Pandas Schema**
+
+```
+data = [[1, 'john@example.com'], [2, 'bob@example.com'], [3, 'john@example.com']]
+person = pd.DataFrame(data, columns=['id', 'email']).astype({'id':'int64', 'email':'object'})
+```
+
+---
+
+### ❗ Solution（`SELF JOIN` 自连接）
+
+<br/>
+
+#### MySQL
+
+```
+DELETE p1
+FROM person AS p1, person AS p2
+WHERE p1.email = p2.email
+AND p1.id > p2.id;
+```
+
+---
+
+### ❗ Solution（`ROW_NUMBER()` 函数）
+
+<br/>
+
+#### MySQL
+
+```
+WITH temp AS (
+    SELECT id, email,
+           ROW_NUMBER() OVER (PARTITION BY email ORDER BY id ASC) AS rn
+    FROM person
+)
+DELETE FROM person
+WHERE id NOT IN (
+    SELECT id FROM temp WHERE rn = 1
+);
+```
+
+<br/>
+
+#### PostgreSQL
+
+```
+WITH temp AS (
+    SELECT id, email,
+           ROW_NUMBER() OVER (PARTITION BY email ORDER BY id ASC) AS rn
+    FROM person
+)
+DELETE FROM person
+WHERE id NOT IN (
+    SELECT id FROM temp WHERE rn = 1
+);
+```
+
+---
+
+### ❗ Solution（`Pandas`）
+
+<br/>
+
+#### Python
+
+```
+import pandas as pd
+
+def delete_duplicate_emails(person: pd.DataFrame) -> None:
+    min_id = person.groupby('email')['id'].transform('min')
+    remove_person = person[person['id'] != min_id]
+    person.drop(remove_person.index, inplace=True)
+    return
+```
diff --git a/markdown/hello/0000.Hello.md b/markdown/hello/0000.Hello.md
@@ -66,6 +66,7 @@
 | <span style="color: #00AF9B;">**Easy**</span>   | [**0182.查找重复的电子邮箱**](../easy/0182.查找重复的电子邮箱.md) |
 | <span style="color: #00AF9B;">**Easy**</span>   | [**0183.从不订购的客户**](../easy/0183.从不订购的客户.md) |
 | <span style="color: #00AF9B;">**Easy**</span>   | [**0191.位1的个数**](../easy/0191.位1的个数.md) |
+| <span style="color: #00AF9B;">**Easy**</span>   | [**0196.删除重复的电子邮箱**](../easy/0196.删除重复的电子邮箱.md) |
 | <span style="color: #00AF9B;">**Easy**</span>   | [**0197.上升的温度**](../easy/0197.上升的温度.md) |
 | <span style="color: #FFB822;">**Medium**</span> | [**0198.打家劫舍**](../medium/0198.打家劫舍.md) |
 | <span style="color: #00AF9B;">**Easy**</span>   | [**0206.反转链表**](../easy/0206.反转链表.md) |
