Done HW6

Sql6.txt

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+Sql6
+#1 Problem 1 : Game Play Analysis II (https://leetcode.com/problems/game-play-analysis-ii/)
+
+WITH CTE AS
+(
+select player_id, device_id, ROW_NUMBER() OVER (partition by player_id order by event_date) as 'rnk' from Activity
+)
+select player_id, device_id from cte where rnk =1;
+
+#2 Problem 2 : Game Play Analysis III (https://leetcode.com/problems/game-play-analysis-iii/)
+
+select player_id, event_date, SUM(games_played) OVER (partition by player_id order by event_date) as 'games_played_so_far' from Activity; 
+
+
+#3 Problem 3 : Shortest Distance in a Plane (https://leetcode.com/problems/shortest-distance-in-a-plane/)
+
+select ROUND(MIN(SQRT(POW(p1.x - p2.x, 2) + POW(p1.y - p2.y, 2))),2) as 'shortest' from Point2D p1 inner join Point2D p2 on (p1.x, p1.y) < (p2.x, p2.y);
+
+
+#4 Problem 4 : Combine Two Tables (https://leetcode.com/problems/combine-two-tables/)
+
+select p.firstName, p.lastName, a.city, a.state from Person p left join Address a on p.personId =a.personId;
+
+#5 Problem 5 : Customers with Strictly Increasing Purchases (https://leetcode.com/problems/customers-with-strictly-increasing-purchases/)
+
+WITH CTE AS 
+( 
+    select customer_id, year(order_date) as 'year', SUM(price) as 'Price' from Orders group by year, customer_id order by customer_id, year
+)
+
+select c1.customer_id from CTE c1 LEFT JOIN CTE c2 on c1.customer_id = c2.customer_id AND c1.year+1 = c2.year AND c1.price < c2.price group by c1.customer_id HAVING count(*)-count(c2.customer_id) =1;