sql3

ActiveUserpast30days.sql

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+SELECT
+    activity_date as 'day',
+    COUNT(DISTINCT user_id) AS active_users
+FROM 
+    Activity
+WHERE 
+    activity_date >= '2019-06-28' AND activity_date <= '2019-07-27'
+GROUP BY(activity_date)

ConsecutiveNumbers.sql

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+# Write your MySQL query statement below
+SELECT DISTINCT l1.num AS ConsecutiveNums FROM Logs l1, Logs l2, Logs l3
+WHERE l1.id = l2.id - 1
+AND l2.id = l3.id - 1
+AND l1.num = l2.num
+AND l2.num = l3.num;

PassengerInEachBus.sql

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+SELECT 
+    b.bus_id,
+    COUNT(p.passenger_id) AS passengers_count
+FROM Buses b
+LEFT JOIN Passengers p 
+    ON p.arrival_time <= b.arrival_time
+GROUP BY b.bus_id
+ORDER BY b.bus_id;