Activity Table Activity:
+ --------- + -------------- +
| Column the Name | Type |
+ -------------- + - + -------
| player_id | int |
| DEVICE_ID | int |
| event_date | DATE |
| games_played | int |
+ ------ + -------------- + ---
table's primary key is (player_id, event_date).
This table shows some gamers behavioral activity in the gaming platform.
Each row of data records the number of games a player before exiting the platform, the day after using the same device to log platform open (possibly 0).
Write a SQL query statement to get the first date of each player landing platform.
Results format is as follows:
Activity 表：
+-----------+-----------+------------+--------------+
| 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 表：
+-----------+-------------+
| player_id | first_login |
+-----------+-------------+
| 1 | 2016-03-01 |
| 2 | 2017-06-25 |
| 3 | 2016-03-02 |
+-----------+-------------+
Ideas: grouped according to the player id, id and minimum time to check.
select player_id,min(event_date) as 'first_login'
from activity
group by player_id
