Done mock sql3

Market Analysis II.sql

@@ -0,0 +1,25 @@
+WITH CTE AS (
+    SELECT o.order_id,o.order_date,o.item_id,o.seller_id,u.favorite_brand, RANK() OVER(PARTITION BY o.seller_id ORDER BY o.order_date) AS rnk
+    FROM
+    Orders o LEFT JOIN Users u
+    ON o.seller_id = u.user_id
+),
+
+CTE2 AS (
+    SELECT c1.seller_id AS 'id'
+    FROM CTE c1 INNER JOIN 
+    Items i
+    ON c1.item_id =  i.item_id AND c1.favorite_brand = i.item_brand
+    WHERE c1.rnk = '2'  
+
+)
+-- SELECT * FROM CTE
+-- SELECT * FROM CTE2
+SELECT a.user_id AS seller_id, CASE
+    WHEN c2.id IS NOT NULL THEN 'yes'
+    ELSE 'no'
+    END
+ AS '2nd_item_fav_brand'
+FROM Users a
+LEFT JOIN CTE2 c2
+ON a.user_id = c2.id

Tournament Winners.sql

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+WITH CTE1 AS(
+    SELECT first_player AS plr, SUM(first_score) AS pts
+    FROM Matches
+    GROUP BY first_player
+UNION ALL
+
+SELECT second_player AS plr, SUM(second_score) AS pts
+    FROM Matches
+    GROUP BY second_player
+
+),
+
+CTE2 AS (
+    SELECT plr, SUM(pts) AS score
+    FROM CTE1
+    GROUP BY plr
+),
+
+
+CTE3 AS(
+SELECT p.group_id, c.plr AS player_id, c.score, RANK() OVER(PARTITION BY group_id ORDER BY score DESC, player_id ASC ) AS rnk
+FROM Players p
+INNER JOIN
+CTE2 c
+ON 
+p.player_id = c.plr
+)
+
+SELECT group_id,  player_id
+FROM CTE3
+WHERE rnk = 1