SQL Server 2019

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CREATE TABLE SkillQuiz (
	Coder VARCHAR(300)
	,SQL int
	,Python int
	);
	
INSERT INTO SkillQuiz (Coder,SQL,Python)
VALUES
    ('Bob', 95, 80),
    ('Emily', 98, 70),
    ('Josh', 60, NULL);
3 rows affected

SELECT *
FROM SkillQuiz


Coder
SQL
Python


Bob
95
80

Emily
98
70

Josh
60
null


SELECT Coder
	,Subject
	,Score
FROM SkillQuiz
UNPIVOT(Score FOR Subject IN (
			SQL
			,Python
			)) AS Unpivoted_Table
ORDER BY Coder
	,Score DESC


Coder
Subject
Score


Bob
SQL
95

Bob
Python
80

Emily
SQL
98

Emily
Python
70

Josh
SQL
60


WITH SkillQuizUnpivot
AS (
	SELECT Coder
		,'SQL' AS Subject
		,SQL AS Score
	FROM SkillQuiz
	
	UNION ALL
	
	SELECT Coder
		,'Python'
		,Python
	FROM SkillQuiz
	)
SELECT *
FROM SkillQuizUnpivot
WHERE Score IS NOT NULL
ORDER BY Coder
	,Score DESC


Coder
Subject
Score


Bob
SQL
95

Bob
Python
80

Emily
SQL
98

Emily
Python
70

Josh
SQL
60


ALTER TABLE SkillQuiz
ADD Java int;
INSERT INTO SkillQuiz (Coder,SQL,Python,Java)
VALUES
    ('Ryan', 95, 90, 70);
1 rows affected

SELECT *
FROM SkillQuiz


Coder
SQL
Python
Java


Bob
95
80
null

Emily
98
70
null

Josh
60
null
null

Ryan
95
90
70


SELECT Coder
	,Subject
	,Score
FROM SkillQuiz
UNPIVOT(Score FOR Subject IN (
			SQL
			,Python
			,Java
			)) AS Unpivoted_Table
ORDER BY Coder
	,Score DESC


Coder
Subject
Score


Bob
SQL
95

Bob
Python
80

Emily
SQL
98

Emily
Python
70

Josh
SQL
60

Ryan
SQL
95

Ryan
Python
90

Ryan
Java
70


WITH SkillQuizUnpivot
AS (
	SELECT Coder
		,'SQL' AS Subject
		,SQL AS Score
	FROM SkillQuiz
	
	UNION ALL
	
	SELECT Coder
		,'Python'
		,Python
	FROM SkillQuiz
	
	UNION ALL
	
	SELECT Coder
		,'Java'
		,Java
	FROM SkillQuiz
	)
SELECT *
FROM SkillQuizUnpivot
WHERE Score IS NOT NULL
ORDER BY Coder
	,Score DESC


Coder
Subject
Score


Bob
SQL
95

Bob
Python
80

Emily
SQL
98

Emily
Python
70

Josh
SQL
60

Ryan
SQL
95

Ryan
Python
90

Ryan
Java
70
Coder	Subject	Score
Bob	SQL	95
Bob	Python	80
Emily	SQL	98
Emily	Python	70
Josh	SQL	60
Ryan	SQL	95
Ryan	Python	90
Ryan	Java	70