sql6 first commit

Combine_Two_Tables.sql

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+#Solution1
+select p.firstname, p.lastname, a.city , a.state from person p left join address a on p.personid = a.personid
+
+#Solution2
+select p.firstname, p.lastname, a.city , a.state from address a right join person p on p.personid = a.personid

Customers_with_Strictly_Increasing_Purchases.sql

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+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 c2.price > c1.price 
+group by c1.customer_id having count(*) - count(c2.customer_id) = 1

Game_Play_AnalysisII.sql

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+#Solution1
+with cte as ( 
+    select player_id, device_id, min(event_date) as 'event_date' from activity 
+    group by player_id ) 
+select a.player_id, a.device_id from activity a 
+    join cte c on a.player_id = c.player_id 
+    and a.event_date = c.event_date;
+
+
+#Solution2
+select distinct a.player_id, first_value(a.device_id) over(partition by a.player_id order by a.event_date) as device_id from activity a
+
+#Solution3
+select a.player_id, a.device_id from activity a where a.event_date in (select min(b.event_date) from activity b where a.player_id = b.player_id);
+
+#Solution4
+with cte as ( select distinct player_id, device_id, rank() over(partition by player_id order by event_date) as 'rnk' from activity)select player_id, device_id from cte where rnk = 1;
+
+#Solution5
+select a1.player_id, a1.device_id from activity a1 where (a1.player_id, a1.event_date) in (select a2.player_id, min(a2.event_date) from activity a2 group by a2.player_id)

Game_Play_Analysis_III.sql

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+#Solution1
+select player_id, event_date, sum( games_played) over (partition by player_id order by event_date) as games_played_so_far from activity 
+
+#Solution2
+select a1.player_id, a1.event_date, sum(a1.games_played) as games_played_so_far from activity a1 inner join activity a2 on a1.player_id = a2.player_id and a1.event_date <= a2.event_date group by a2.player_id,a2.event_date
+
+#Solution3
+select a1.player_id, a1.event_date, (select sum(a2.games_played) from activity a2 where a1.player_id = a2.player_id and a2.event_date <= a1.event_date) as 'games_played_so_far' from activity a1;

Shortest_Distance_in_a_Plane.sql

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+#Solution1
+select round(sqrt(min(pow(p2.x-p1.x,2)+pow(p2.y-p1.y,2))),2) as 'shortest' from point2d p1 inner join point2d p2 on p1.x != p2.x or p1.y != p2.y
+
+#Solution2
+select round(sqrt(min(pow(p2.x-p1.x,2)+pow(p2.y-p1.y,2))),2) as 'shortest' from point2d p1 inner join point2d p2 on 
+p1.x <= p2.x and p1.y < p2.y or 
+p1.x <= p2.x and p1.y > p2.y or
+p1.x > p2.x and p1.y = p2.y