This Leetcode problem User Activity for the Past 30 Days I LeetCode Solution is done in SQL.
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User Activity for the Past 30 Days I LeetCode Solution
Table of Contents
Problem Statement
| Column Name | Type |
| user_id | int |
| session_id | int |
| activity_date | date |
| activity_type | enum |
ActivityThis table may have duplicate rows.
The activity_type column is an ENUM (category) of type (‘open_session’, ‘end_session’, ‘scroll_down’, ‘send_message’). The table shows the user activities for a social media website. Note that each session belongs to exactly one user.
Write a solution to find the daily active user count for a period of 30 days ending 2019-07-27 inclusively. A user was active on someday if they made at least one activity on that day.
Return the result table in any order.
The result format is in the following example.
Example 1:
Input:
| user_id | session_id | activity_date | activity_type |
| 1 | 1 | 2019-07-20 | open_session |
| 1 | 1 | 2019-07-20 | scroll_down |
| 1 | 1 | 2019-07-20 | end_session |
| 2 | 4 | 2019-07-20 | open_session |
| 2 | 4 | 2019-07-21 | send_message |
| 2 | 4 | 2019-07-21 | end_session |
| 3 | 2 | 2019-07-21 | open_session |
| 3 | 2 | 2019-07-21 | send_message |
| 3 | 2 | 2019-07-21 | end_session |
| 4 | 3 | 2019-06-25 | open_session |
| 4 | 3 | 2019-06-25 | end_session |
Output:
| day | active_users |
| 2019-07-20 | 2 |
| 2019-07-21 | 2 |
Explanation: Note that we do not care about days with zero active users.
User Activity for the Past 30 Days I LeetCode Solution MySQL
select
activity_date as day,
count(distinct user_id) as active_users
from
Activity
where
activity_date between '2019-06-28'
and '2019-07-27'
group by
day;Code language: SQL (Structured Query Language) (sql)