1517. Find Users With Valid E-Mails
Description of Problem
Table: Users
+---------------+---------+
| Column Name | Type |
+---------------+---------+
| user_id | int |
| name | varchar |
| mail | varchar |
+---------------+---------+
user_id is the primary key (column with unique values) for this table.
This table contains information of the users signed up in a website. Some e-mails are invalid.
Write a solution to find the users who have valid emails.
A valid e-mail has a prefix name and a domain where:
- The prefix name is a string that may contain letters (upper or lower case), digits, underscore
'_', period'.', and/or dash'-'. The prefix name must start with a letter. - The domain is
'@leetcode.com'. Return the result table in any order.
The result format is in the following example.
Example 1:
Input:
Users table:
+---------+-----------+-------------------------+
| user_id | name | mail |
+---------+-----------+-------------------------+
| 1 | Winston | winston@leetcode.com |
| 2 | Jonathan | jonathanisgreat |
| 3 | Annabelle | bella-@leetcode.com |
| 4 | Sally | sally.come@leetcode.com |
| 5 | Marwan | quarz#2020@leetcode.com |
| 6 | David | david69@gmail.com |
| 7 | Shapiro | .shapo@leetcode.com |
+---------+-----------+-------------------------+
Output:
+---------+-----------+-------------------------+
| user_id | name | mail |
+---------+-----------+-------------------------+
| 1 | Winston | winston@leetcode.com |
| 3 | Annabelle | bella-@leetcode.com |
| 4 | Sally | sally.come@leetcode.com |
+---------+-----------+-------------------------+
Explanation:
The mail of user 2 does not have a domain.
The mail of user 5 has the # sign which is not allowed.
The mail of user 6 does not have the leetcode domain.
The mail of user 7 starts with a period.
Solution
Tags: SQL
Code (MySQL)
-- Write your MySQL query statement below
SELECT *
FROM Users
WHERE mail REGEXP '^[A-Za-z][A-Za-z0-9_.-]*@leetcode\\.com$';