Question

511. Game Play Analysis I

中文文档

Description

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 (combination of columns with unique values) of this table.
This table shows the activity of players of some games.
Each row is a record of a player who logged in and played a number of games (possibly 0) before logging out on someday using some device.

 

Write a solution to find the first login date for each player.

Return the result table in any order.

The result format is in the following example.

 

Example 1:

Input: 
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      |
+-----------+-----------+------------+--------------+
Output: 
+-----------+-------------+
| player_id | first_login |
+-----------+-------------+
| 1     | 2016-03-01  |
| 2     | 2017-06-25  |
| 3     | 2016-03-02  |
+-----------+-------------+

Solutions

Solution 1: Group By + Min Function

We can use GROUP BY to group the player_id and then take the minimum event_date in each group as the date when the player first logged into the platform.

import pandas as pd


def game_analysis(activity: pd.DataFrame) -> pd.DataFrame:
  return (
    activity.groupby("player_id")
    .agg(first_login=("event_date", "min"))
    .reset_index()
  )

# Write your MySQL query statement below
SELECT player_id, MIN(event_date) AS first_login
FROM Activity
GROUP BY 1;