Update Advanced SQL Puzzles Solutions.sql

Author: smpetersgithub

Advanced SQL Puzzles/Advanced SQL Puzzles Solutions.sql

@@ -1181,6 +1181,8 @@ INSERT INTO #Orders VALUES
 ('Ord645363',2002,5,'Direct Parts');
 GO
 
+--Solution 1
+--RANK function
 WITH cte_Rank AS
 (
 SELECT  CustomerID,
@@ -1195,6 +1197,33 @@ FROM    #Orders a INNER JOIN
 WHERE   Rnk = 1;
 GO
 
+--Solution 2
+--MAX Function
+WITH cte_Max AS
+(
+SELECT  *,
+        MAX(Ordercount) OVER (PARTITION BY CustomerID ORDER BY CustomerID) AS MaxOrderCount
+FROM    #Orders
+)
+SELECT  CustomerID, Vendor
+FROM    cte_Max
+WHERE   OrderCount = MaxOrderCount;
+GO
+
+--Solution 3
+--MAX with Correlated SubQuery
+WITH cte_Max AS
+(
+SELECT  CustomerID,
+        MAX(OrderCount) AS MaxOrderCount
+FROM    #Orders
+GROUP BY CustomerID
+)
+SELECT  *
+FROM    #Orders a
+WHERE EXISTS (SELECT 1 FROM cte_Max b WHERE a.CustomerID = b.CustomerID and a.OrderCount = MaxOrderCount);
+GO
+
 /*----------------------------------------------------
 Answer to Puzzle #26
 Previous Years Sales