Completed Sql3

ConsecutiveNumbers.sql

@@ -0,0 +1,9 @@
+'''
+Sql3
+
+1 Problem 1 : Consecutive Numbers (https://leetcode.com/problems/consecutive-numbers/)
+'''
+
+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)

DynamicPivotingOfATable.sql

@@ -0,0 +1,18 @@
+'''
+4 Problem 4 :Dynamic Pivoting of a Table ( https://leetcode.com/problems/dynamic-pivoting-of-a-table/ )
+'''
+
+CREATE PROCEDURE PivotProducts()
+BEGIN
+	# Write your MySQL query statement below.
+SET GROUP_CONCAT_MAX_LEN = 1000000;    
+    SELECT GROUP_CONCAT(DISTINCT CONCAT('SUM(IF(store = "', store, '", price, null)) as ' , store))
+    INTO @sql FROM products;
+
+    SET @sql = CONCAT('SELECT product_id,', @sql, ' FROM Products GROUP BY 1');
+
+    PREPARE statement FROM @sql;
+    EXECUTE statement;
+    DEALLOCATE PREPARE STATEMENT;
+
+END

NumberOfPassengersInEachBus.sql

@@ -0,0 +1,16 @@
+'''
+2 Problem 2 :Number of Passengers in Each Bus ( https://leetcode.com/problems/the-number-of-passengers-in-each-bus-i/ )
+
+'''
+
+WITH CTE AS (
+    SELECT passenger_id, Passengers.arrival_time, MIN(Buses.arrival_time) AS btime
+    FROM Passengers
+    JOIN Buses ON Passengers.arrival_time <= Buses.arrival_time
+    GROUP BY passenger_id
+)
+SELECT bus_id, COUNT(btime) AS Passengers_cnt
+FROM Buses
+LEFT JOIN CTE ON btime = Buses.arrival_time
+GROUP BY bus_id
+ORDER BY bus_id

UserActivity.sql

@@ -0,0 +1,8 @@
+'''
+3 Problem 3 :User Activity (https://leetcode.com/problems/user-activity-for-the-past-30-days-i/ )
+'''
+
+SELECT activity_date AS day, COUNT(DISTINCT user_id) AS active_users
+FROM Activity
+WHERE activity_date BETWEEN '2019-06-28' AND '2019-07-27'
+GROUP BY day