Check the below input data and require output data to find max value from multiple columns.

Input Data:

Class      Mark1       Mark2       Mark3
---------- ----------- ----------- -----------
A          88          98          52
B          85          54          93
C          65          87          45
D          35          77          63

Require output data:

Class      MaxMarks
---------- -----------
A          98
B          93
C          87
D          77

Create a table with sample data:

CREATE TABLE MaxClassMarks
(
	Class VARCHAR(10)
	,Mark1 INT
	,Mark2 INT
	,Mark3 INT
)
GO

INSERT INTO MaxClassMarks 
VALUES
 ('A',88,98,52)
,('B',85,54,93)
,('C',65,87,45)
,('D',35,77,63)
GO

Solution 1: Use CASE .. WHEN

SELECT Class,
       CASE WHEN mark1 > mark2 AND mark1 > mark3 THEN mark1
       WHEN mark2 > mark1 AND mark2 > mark3 THEN mark2
       WHEN mark3 > mark2 AND mark3 > mark1 THEN mark3
       END AS MaxMarks
FROM MaxClassMarks

Solution 2: Use Subquery and MAX()

SELECT Class,
(
       SELECT Max(T)
       FROM (
              VALUES (mark1) , (mark2), (mark3) 
       ) as value(T)
) as maxmark
FROM MaxClassMarks

Solution 3: Use MAX() with Group BY

SELECT Class, MAX(maxmark) maxmark
FROM
(
       SELECT Class , mark1 as maxmark FROM MaxClassMarks
       UNION ALL
       SELECT Class , mark2 as maxmark FROM MaxClassMarks
       UNION ALl
       SELECT Class , mark3 as maxmark FROM MaxClassMarks
) a GROUP BY Class

Please try the different solution for this puzzle and share it via comment...

In this post, I am sharing a T-SQL Script to find the MAX value from Multiple columns in SQL Server.

For example:
In our table, we have three different date columns and need to find the one max value out of this three columns.

I worked around this and tested different solution for the performance. I am sharing one of the best solutions here.

I have tested different solutions like UNPIVOT, UNION, InnerQuery.

Note: Below T-SQL script solution work with the only same type of columns.

Let’s First, create sample table and data:

CREATE TABLE tbl_FindMAX
(
	ID INT IDENTITY(1,1) PRIMARY KEY
	,Name NVARCHAR(255)
	,UpdatedDate1 DATETIME
	,UpdatedDate2 DATETIME
	,UpdatedDate3 DATETIME
)

INSERT INTO tbl_FindMAX(Name, UpdatedDate1, UpdatedDate2, UpdatedDate3 )
VALUES('Anvesh', '2015-08-08','2015-10-10', '2015-11-08'),
	  ('Neevan', '2015-08-26','2010-10-08', '2015-05-16'),
	  ('Akash', '2014-02-26','2014-02-16', '2015-08-16')

T-SQL Script to Find MAX Value from three different Date Columns:

SELECT 
   ID, 
   (SELECT MAX(LastUpdateDate)
      FROM (VALUES (UpdatedDate1),(UpdatedDate2),(UpdatedDate3)) AS UpdateDate(LastUpdateDate)) 
   AS LastUpdateDate
FROM tbl_FindMAX

The Result: