SQL 6 Done

Combine_Two_Tables.txt

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+SELECT P.firstName, P.LastName, A.City, A.state from Person P left join address A on P.personId = A.personID;

Customers_with_Strictly_Increasing_Purchase.txt

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+WITH CTE AS (
+    SELECT CUSTOMER_ID,YEAR(ORDER_DATE)AS YEARS ,SUM(PRICE) AS S_PRICE FROM ORDERS GROUP BY CUSTOMER_ID,YEARS ORDER BY CUSTOMER_ID,YEARS
+)
+SELECT C1.CUSTOMER_ID FROM CTE C1  LEFT JOIN CTE C2 ON C1.CUSTOMER_ID = C2.CUSTOMER_ID AND C1.YEARS + 1 = C2.YEARS AND C1.S_PRICE < C2.S_PRICE GROUP BY C1.CUSTOMER_ID HAVING COUNT(*) - COUNT(C2.CUSTOMER_ID) = 1;

Gameplay_Analysis_II.txt

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+select Player_id, device_id from (select distinct player_id,rank()  over (partition by player_id order by event_date) as rnk , device_id from activity) a where a.rnk = 1;

Gameplay_Analysis_III.txt

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+SELECT player_id, event_date, 
+SUM(games_played) OVER (PARTITION BY player_id ORDER BY event_date) AS games_played_so_far 
+FROM Activity;

Shortest_Distance_Between_two_Plane.txt

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+SELECT
+    ROUND(MIN(SQRT(POWER(p1.x - p2.x, 2) + POWER(p1.y - p2.y, 2))), 2) AS shortest
+FROM
+    Point2D p1
+JOIN
+    Point2D p2
+ON
+    p1.x != p2.x OR p1.y != p2.y;