LeetCode in Kotlin
3436. Find Valid Emails
Easy
Table: Users
+-----------------+---------+
| Column Name | Type |
+-----------------+---------+
| user_id | int |
| email | varchar |
+-----------------+---------+
(user_id) is the unique key for this table.
Each row contains a user's unique ID and email address.
Write a solution to find all the valid email addresses. A valid email address meets the following criteria:
- It contains exactly one
@symbol. - It ends with
.com. - The part before the
@symbol contains only alphanumeric characters and underscores. - The part after the
@symbol and before.comcontains a domain name that contains only letters.
Return the result table ordered by user_id in ascending order.
Example:
Input:
Users table:
+---------+---------------------+
| user_id | email |
+---------+---------------------+
| 1 | alice@example.com |
| 2 | bob_at_example.com |
| 3 | charlie@example.net |
| 4 | david@domain.com |
| 5 | eve@invalid |
+---------+---------------------+
Output:
+---------+-------------------+
| user_id | email |
+---------+-------------------+
| 1 | alice@example.com |
| 4 | david@domain.com |
+---------+-------------------+
Explanation:
- alice@example.com is valid because it contains one
@, alice is alphanumeric, and example.com starts with a letter and ends with .com. - bob_at_example.com is invalid because it contains an underscore instead of an
@. - charlie@example.net is invalid because the domain does not end with
.com. - david@domain.com is valid because it meets all criteria.
- eve@invalid is invalid because the domain does not end with
.com.
Result table is ordered by user_id in ascending order.
Solution
# Write your MySQL query statement below
select user_id, email from users
where email regexp '^[A-Za-z0-9_]+@[A-Za-z][A-Za-z0-9_]*\.com$'
order by user_id