Get the Maximum Value Across Columns in TSQL

The following example shows how to get max value across columns in a table:

--////////////////////////////////////////////////
CREATE TABLE #tblScores (
StudentID INT PRIMARY KEY,
Maths INT,Physics INT,History INT,Chemistry INT
)

INSERT INTO #tblScores values (1,90,70,75,65)
INSERT INTO #tblScores values (2,80,65,85,70)
INSERT INTO #tblScores values (3,65,60,55,40)
INSERT INTO #tblScores values (4,85,70,75,65)
INSERT INTO #tblScores values (5,50,80,70,50)

--SELECT * FROM #tblScores

SELECT StudentID, Maths, Physics, History, Chemistry ,
	CASE WHEN Maths < Physics THEN
	      CASE WHEN Physics < History THEN
		 CASE WHEN History < Chemistry THEN
			Chemistry
		 ELSE
			History
		 END
	      ELSE
		 CASE WHEN Physics < Chemistry THEN
			Chemistry
		 ELSE
			Physics
		 END
	      END
	ELSE
	      CASE WHEN Maths < History THEN
		 CASE WHEN History < Chemistry THEN
			Chemistry
		 ELSE
			History
		 END

	 ELSE
		 CASE WHEN Maths < Chemistry THEN
			Chemistry
		 ELSE
			Maths
		 END
	      END
	END as AllMAX
FROM #tblScores
--///////////////////////////////////////////////