Added task 3497

src/main/java/g3401_3500/s3497_analyze_subscription_conversion/readme.md

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+3497\. Analyze Subscription Conversion
+
+Medium
+
+Table: `UserActivity`
+
+    +------------------+---------+
+    | Column Name      | Type    |
+    +------------------+---------+
+    | user_id          | int     |
+    | activity_date    | date    |
+    | activity_type    | varchar |
+    | activity_duration| int     |
+    +------------------+---------+
+    (user_id, activity_date, activity_type) is the unique key for this table. activity_type is one of ('free_trial', 'paid', 'cancelled').
+    activity_duration is the number of minutes the user spent on the platform that day.
+    Each row represents a user's activity on a specific date. 
+
+A subscription service wants to analyze user behavior patterns. The company offers a `7`\-day **free trial**, after which users can subscribe to a **paid plan** or **cancel**. Write a solution to:
+
+1.  Find users who converted from free trial to paid subscription
+2.  Calculate each user's **average daily activity duration** during their **free trial** period (rounded to `2` decimal places)
+3.  Calculate each user's **average daily activity duration** during their **paid** subscription period (rounded to `2` decimal places)
+
+Return _the result table ordered by_ `user_id` _in **ascending** order_.
+
+The result format is in the following example.
+
+**Example:**
+
+**Input:**
+
+UserActivity table:
+
+| user_id | activity_date | activity_type | activity_duration |
+|---------|---------------|---------------|-------------------|
+| 1       | 2023-01-01    | free_trial    | 45                |
+| 1       | 2023-01-02    | free_trial    | 30                |
+| 1       | 2023-01-05    | free_trial    | 60                |
+| 1       | 2023-01-10    | paid          | 75                |
+| 1       | 2023-01-12    | paid          | 90                |
+| 1       | 2023-01-15    | paid          | 65                |
+| 2       | 2023-02-01    | free_trial    | 55                |
+| 2       | 2023-02-03    | free_trial    | 25                |
+| 2       | 2023-02-07    | free_trial    | 50                |
+| 2       | 2023-02-10    | cancelled     | 0                 |
+| 3       | 2023-03-05    | free_trial    | 70                |
+| 3       | 2023-03-06    | free_trial    | 60                |
+| 3       | 2023-03-08    | free_trial    | 80                |
+| 3       | 2023-03-12    | paid          | 50                |
+| 3       | 2023-03-15    | paid          | 55                |
+| 3       | 2023-03-20    | paid          | 85                |
+| 4       | 2023-04-01    | free_trial    | 40                |
+| 4       | 2023-04-03    | free_trial    | 35                |
+| 4       | 2023-04-05    | paid          | 45                |
+| 4       | 2023-04-07    | cancelled     | 0                 |
+
+**Output:**
+
+| user_id | trial_avg_duration | paid_avg_duration |
+|---------|--------------------|-------------------|
+| 1       | 45.00              | 76.67             |
+| 3       | 70.00              | 63.33             |
+| 4       | 37.50              | 45.00             |
+
+**Explanation:**
+
+*   **User 1:**
+    *   Had 3 days of free trial with durations of 45, 30, and 60 minutes.
+    *   Average trial duration: (45 + 30 + 60) / 3 = 45.00 minutes.
+    *   Had 3 days of paid subscription with durations of 75, 90, and 65 minutes.
+    *   Average paid duration: (75 + 90 + 65) / 3 = 76.67 minutes.
+*   **User 2:**
+    *   Had 3 days of free trial with durations of 55, 25, and 50 minutes.
+    *   Average trial duration: (55 + 25 + 50) / 3 = 43.33 minutes.
+    *   Did not convert to a paid subscription (only had free\_trial and cancelled activities).
+    *   Not included in the output because they didn't convert to paid.
+*   **User 3:**
+    *   Had 3 days of free trial with durations of 70, 60, and 80 minutes.
+    *   Average trial duration: (70 + 60 + 80) / 3 = 70.00 minutes.
+    *   Had 3 days of paid subscription with durations of 50, 55, and 85 minutes.
+    *   Average paid duration: (50 + 55 + 85) / 3 = 63.33 minutes.
+*   **User 4:**
+    *   Had 2 days of free trial with durations of 40 and 35 minutes.
+    *   Average trial duration: (40 + 35) / 2 = 37.50 minutes.
+    *   Had 1 day of paid subscription with duration of 45 minutes before cancelling.
+    *   Average paid duration: 45.00 minutes.
+
+The result table only includes users who converted from free trial to paid subscription (users 1, 3, and 4), and is ordered by user\_id in ascending order.

src/main/java/g3401_3500/s3497_analyze_subscription_conversion/script.sql

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+# Write your MySQL query statement below
+# #Medium #2025_03_29_Time_347_ms_(100.00%)_Space_0.0_MB_(100.00%)
+SELECT 
+    ft.user_id,
+    ROUND(ft.avg_trial, 2) AS trial_avg_duration,
+    ROUND(pt.avg_paid, 2) AS paid_avg_duration
+FROM
+    (SELECT user_id, AVG(activity_duration) AS avg_trial
+     FROM UserActivity
+     WHERE activity_type = 'free_trial'
+     GROUP BY user_id) ft
+JOIN
+    (SELECT user_id, AVG(activity_duration) AS avg_paid
+     FROM UserActivity
+     WHERE activity_type = 'paid'
+     GROUP BY user_id) pt
+ON ft.user_id = pt.user_id
+ORDER BY ft.user_id ASC;

src/test/java/g3401_3500/s3497_analyze_subscription_conversion/MysqlTest.java

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+package g3401_3500.s3497_analyze_subscription_conversion;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.stream.Collectors;
+import javax.sql.DataSource;
+import org.junit.jupiter.api.Test;
+import org.zapodot.junit.db.annotations.EmbeddedDatabase;
+import org.zapodot.junit.db.annotations.EmbeddedDatabaseTest;
+import org.zapodot.junit.db.common.CompatibilityMode;
+
+@EmbeddedDatabaseTest(
+        compatibilityMode = CompatibilityMode.MySQL,
+        initialSqls =
+                "    CREATE TABLE UserActivity ("
+                        + "    user_id INT,"
+                        + "    activity_date date,"
+                        + "    activity_type VARCHAR(100),"
+                        + "    activity_duration INT"
+                        + ");"
+                        + "INSERT INTO UserActivity (user_id, activity_date, activity_type, activity_duration)"
+                        + "VALUES"
+                        + "    (1, '2023-01-01', 'free_trial', 45),"
+                        + "    (1, '2023-01-02', 'free_trial', 30),"
+                        + "    (1, '2023-01-05', 'free_trial', 60),"
+                        + "    (1, '2023-01-10', 'paid', 75),"
+                        + "    (1, '2023-01-12', 'paid', 90),"
+                        + "    (1, '2023-01-15', 'paid', 65),"
+                        + "    (2, '2023-02-01', 'free_trial', 55),"
+                        + "    (2, '2023-02-03', 'free_trial', 25),"
+                        + "    (2, '2023-02-07', 'free_trial', 50),"
+                        + "    (2, '2023-02-10', 'cancelled', 0),"
+                        + "    (3, '2023-03-05', 'free_trial', 70),"
+                        + "    (3, '2023-03-06', 'free_trial', 60),"
+                        + "    (3, '2023-03-08', 'free_trial', 80),"
+                        + "    (3, '2023-03-12', 'paid', 50),"
+                        + "    (3, '2023-03-15', 'paid', 55),"
+                        + "    (3, '2023-03-20', 'paid', 85),"
+                        + "    (4, '2023-04-01', 'free_trial', 40),"
+                        + "    (4, '2023-04-03', 'free_trial', 35),"
+                        + "    (4, '2023-04-05', 'paid', 45),"
+                        + "    (4, '2023-04-07', 'cancelled', 0);")
+class MysqlTest {
+    @Test
+    void testScript(@EmbeddedDatabase DataSource dataSource)
+            throws SQLException, FileNotFoundException {
+        try (final Connection connection = dataSource.getConnection()) {
+            try (final Statement statement = connection.createStatement();
+                    final ResultSet resultSet =
+                            statement.executeQuery(
+                                    new BufferedReader(
+                                                    new FileReader(
+                                                            "src/main/java/g3401_3500/"
+                                                                    + "s3497_analyze_subscription_conversion/"
+                                                                    + "script.sql"))
+                                            .lines()
+                                            .collect(Collectors.joining("\n"))
+                                            .replaceAll("#.*?\\r?\\n", ""))) {
+                checkRow(resultSet, new String[] {"1", "45.0", "76.67"});
+                checkRow(resultSet, new String[] {"3", "70.0", "63.33"});
+                checkRow(resultSet, new String[] {"4", "37.5", "45.0"});
+                assertThat(resultSet.next(), equalTo(false));
+            }
+        }
+    }
+
+    private void checkRow(ResultSet resultSet, String[] values) throws SQLException {
+        assertThat(resultSet.next(), equalTo(true));
+        assertThat(resultSet.getNString(1), equalTo(values[0]));
+        assertThat(resultSet.getNString(2), equalTo(values[1]));
+        assertThat(resultSet.getNString(3), equalTo(values[2]));
+    }
+}