completed sql3

1st problem.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 L1.num=L2.num 
+and  L1.id=L3.id-2 and L1.num=L3.num;

2nd problem.sql

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+# Write your MySQL query statement below
+WITH t AS
+(
+    SELECT passenger_id, MIN(b.arrival_time) AS arrival_time
+    FROM Passengers p
+    INNER JOIN Buses b
+    ON p.arrival_time <= b.arrival_time
+    GROUP BY passenger_id
+)
+
+SELECT bus_id, COUNT(t.arrival_time) AS passengers_cnt
+FROM Buses b
+LEFT JOIN t
+ON b.arrival_time = t.arrival_time
+GROUP BY bus_id
+ORDER BY bus_id

3rd problem.sql

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+SELECT activity_date as day, count(distinct user_id) as active_users from Activity
+group by activity_date
+having activity_date>="2019-06-28" and activity_date<="2019-07-27";

4th problem.sql

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+CREATE PROCEDURE PivotProducts()
+BEGIN
+	# Write your MySQL query statement below.
+    SET group_concat_max_len = 1000000; 
+    SET @sql = NULL;
+    SELECT
+    GROUP_CONCAT(DISTINCT CONCAT(
+      'SUM(IF(store = "', store, '", price, null)) AS ', store) ORDER BY store ASC)
+    INTO @sql
+    FROM Products;
+
+    SET @sql = CONCAT('SELECT product_id, ', @sql, ' FROM Products GROUP BY product_id');
+
+
+    PREPARE stmt FROM @sql;
+    EXECUTE stmt;
+    DEALLOCATE PREPARE stmt;
+END