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49 lines
1.5 KiB
HTML
49 lines
1.5 KiB
HTML
<p>Table: <code>Activity</code></p>
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<pre>
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+--------------+---------+
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| Column Name | Type |
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+--------------+---------+
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| player_id | int |
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| device_id | int |
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| event_date | date |
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| games_played | int |
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+--------------+---------+
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(player_id, event_date) is the primary key of this table.
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This table shows the activity of players of some games.
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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.
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</pre>
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<p> </p>
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<p>Write an SQL query to report the <strong>first login date</strong> for each player.</p>
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<p>Return the result table in <strong>any order</strong>.</p>
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<p>The query result format is in the following example.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong>
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Activity table:
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+-----------+-----------+------------+--------------+
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| player_id | device_id | event_date | games_played |
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+-----------+-----------+------------+--------------+
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| 1 | 2 | 2016-03-01 | 5 |
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| 1 | 2 | 2016-05-02 | 6 |
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| 2 | 3 | 2017-06-25 | 1 |
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| 3 | 1 | 2016-03-02 | 0 |
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| 3 | 4 | 2018-07-03 | 5 |
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+-----------+-----------+------------+--------------+
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<strong>Output:</strong>
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+-----------+-------------+
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| player_id | first_login |
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+-----------+-------------+
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| 1 | 2016-03-01 |
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| 2 | 2017-06-25 |
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| 3 | 2016-03-02 |
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+-----------+-------------+
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</pre>
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