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47 lines
1.8 KiB
HTML
47 lines
1.8 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 (combination of columns with unique values) 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 a solution to report the <strong>fraction</strong> of players that logged in again on the day after the day they first logged in, <strong>rounded to 2 decimal places</strong>. In other words, you need to determine the number of players who logged in on the day immediately following their initial login, and divide it by the number of total players.</p>
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<p>The result format is in the following example.</p>
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<p> </p>
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<p><strong class="example">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 | 2016-03-02 | 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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| fraction |
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+-----------+
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| 0.33 |
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+-----------+
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<strong>Explanation:</strong>
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Only the player with id 1 logged back in after the first day he had logged in so the answer is 1/3 = 0.33
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</pre>
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