SQL LeetCode: 512. Game Play Analysis II

Pallavi Mirajkar Dantkale
1 min readApr 5, 2021

512. Game Play Analysis II

Table: Activity

+--------------+---------+
| Column Name | Type |
+--------------+---------+
| player_id | int |
| device_id | int |
| event_date | date |
| games_played | int |
+--------------+---------+
(player_id, event_date) is the primary key of this table.
This table shows the activity of players of some game.
Each row is a record of a player who logged in and played a number of games (possibly 0) before logging out on some day using some device.

Write a SQL query that reports the device that is first logged in for each player.

The query result format is in the following example:

Activity table:
+-----------+-----------+------------+--------------+
| player_id | device_id | event_date | games_played |
+-----------+-----------+------------+--------------+
| 1 | 2 | 2016-03-01 | 5 |
| 1 | 2 | 2016-05-02 | 6 |
| 2 | 3 | 2017-06-25 | 1 |
| 3 | 1 | 2016-03-02 | 0 |
| 3 | 4 | 2018-07-03 | 5 |
+-----------+-----------+------------+--------------+
Result table:
+-----------+-----------+
| player_id | device_id |
+-----------+-----------+
| 1 | 2 |
| 2 | 3 |
| 3 | 1 |
+-----------+-----------+

SELECT
player_id,
device_id
FROM (

SELECT
player_id,
device_id,
dense_rank() OVER (PARTITION BY player_id order by event_date asc) as rank_device
FROM
Activity
) AS denserank_device
where rank_device = 1

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Pallavi Mirajkar Dantkale
Pallavi Mirajkar Dantkale

Written by Pallavi Mirajkar Dantkale

QA Engineer / Data Analyst — Highly committed to Quality Assurance and data analysis, advocate for quality and add the right value to the organization.

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