Last updated on January 21st, 2025 at 09:54 pm

Here, we see the Article Views I LeetCode Solution. This Leetcode problem is solved using MySQL and Pandas.

List of all LeetCode Solution

Level of Question

Easy

Article Views I LeetCode Solution

1. Problem Statement

Column Name	Type
article_id	int
author_id	int
viewer_id	int
view_date	date

There is no primary key (column with unique values) for this table, the table may have duplicate rows.
Each row of this table indicates that some viewer viewed an article (written by some author) on some date. Note that equal author_id and viewer_id indicate the same person.

Write a solution to find all the authors that viewed at least one of their own articles.

Return the result table sorted by id in ascending order.

The result format is in the following example.

Example 1:
Input:

article_id	author_id	viewer_id	view_date
1	3	5	2019-08-01
1	3	6	2019-08-02
2	7	7	2019-08-01
2	7	6	2019-08-02
4	7	1	2019-07-22
3	4	4	2019-07-21
3	4	4	2019-07-21

Output:

id

4

7

2. Code Implementation in Different Languages

2.1 Article Views I MySQL

select 
  distinct author_id as id 
from 
  Views 
where 
  author_id = viewer_id 
order by 
  author_id;