SQL PUZZLE | Find Maximum value record for each Id? | A SINGLE SELECT Interview Question

In this puzzle you have to find the maximum value for each Id and then get the Item for that Id and Maximum value. The Challenge is to do that in a SINGLE SELECT. Please check out sample input and expected output.

Sample Input

Expected output

Script – DDL and INSERT sample data

--

CREATE TABLE TestMaximum
(
     [ID] INT
    ,[Item] VARCHAR(20)
	,Vals INT
)

INSERT TestMaximum VALUES
(1, 'a1',15),
(1, 'a2',20),
(1, 'a3',90),
(2, 'q1',10),
(2, 'q2',40),
(2, 'q3',60),
(2, 'q4',30),
(3, 'q5',20);

SELECT * FROM TestMaximum
GO

--

SOLUTION – 1

--

SELECT TOP 1 WITH TIES [ID], [Item], Vals
FROM TestMaximum
ORDER BY ROW_NUMBER() OVER (PARTITION BY [ID] ORDER BY Vals DESC)

--

OUTPUT – 1

--

ID          Item                 Vals
----------- -------------------- -----------
2           q3                   60
1           a3                   90
3           q5                   20

(3 rows affected)

--

Enjoy 🙂

Please add comment(s) if you have one or multiple solutions in mind. Thank You.

Pawan Khowal

Pawan is a SQL Server Developer. If you need any help in writing code/puzzle or training please email at – pawankkmr”AT”gmail.com. Meanwhile please go throgh the top pages from his blog.

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