Completed Sql3

Problem 1.txt

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+Select distinct(t1.num) as ConsecutiveNums from logs t1, logs t2, logs t3
+where t1.id = t2.id+1 and t2.id = t3.id+1 and t1.num = t2.num and t3.num = t2.num
+

Problem 2.txt

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+with cte as (
+  Select p.passenger_id, min(b.arrival_time) as arrival_time from buses b 
+  inner join Passengers p on p.arrival_time<=b.arrival_time
+  group by passenger_id
+)
+Select b.bus_id, count(cte.arrival_time) as passengers_cnt
+from buses b
+left join cte on b.arrival_time = cte.arrival_time
+group by bus_id
+order by bus_id

Problem 3.txt

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

Problem 4.txt

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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))into @sql from Products;
+    SET @sql = CONCAT('SELECT product_id, ', @sql, ' FROM Products GROUP BY product_id');
+    PREPARE STATEMENT from @sql;
+    EXECUTE STATEMENT;
+    DEALLOCATE PREPARE STATEMENT;
+END