Algorithm

Problem Name: 182. Duplicate Emails

Problem Link: https://leetcode.com/problems/duplicate-emails/
 
SQL Schema

Table: Person

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| id          | int     |
| email       | varchar |
+-------------+---------+
id is the primary key column for this table.
Each row of this table contains an email. The emails will not contain uppercase letters.

 

Write an SQL query to report all the duplicate emails.

Return the result table in any order.

The query result format is in the following example.

 

Example 1:

Input: 
Person table:
+----+---------+
| id | email   |
+----+---------+
| 1  | a@b.com |
| 2  | c@d.com |
| 3  | a@b.com |
+----+---------+
Output: 
+---------+
| Email   |
+---------+
| a@b.com |
+---------+
Explanation: a@b.com is repeated two times.

 

Code Examples

#1 Code Example with SQL

Code - SQL


select Email
from
    (
  select Email, count(Email) as num
    from Person
    group by Email
) as statistic
where num > 1
;
Copy The Code & Try With Live Editor

Input

x
–
+
cmd
Person table: +----+---------+ | id | email | +----+---------+ | 1 | a@b.com | | 2 | c@d.com | | 3 | a@b.com | +----+---------+

Output

x
–
+
cmd
+---------+ | Email | +---------+ | a@b.com | +---------+
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Demonstration

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