SQL Server 2019

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CREATE TABLE city
(COUNTRYCODE VARCHAR(3),
DISTRICT VARCHAR(30),
POPULATION INT);
INSERT INTO CITY VALUES ('ANT','Curacao',2345);
INSERT INTO CITY VALUES ('ARG','Catamarca',134935);
INSERT INTO CITY VALUES ('BLZ','Cayo',7105);
INSERT INTO CITY VALUES ('COL','Caldas',337580);
INSERT INTO CITY VALUES ('ARG','Chaco',229212);
INSERT INTO CITY VALUES ('COL','Caqueta',108574);
6 rows affected

SELECT CountryCode, District, MAX(Population) AS Population
FROM city
WHERE District LIKE 'C%' OR District LIKE 'D%'
GROUP BY CountryCode, District
ORDER BY CountryCode, District


CountryCode
District
Population


ANT
Curacao
2345

ARG
Catamarca
134935

ARG
Chaco
229212

BLZ
Cayo
7105

COL
Caldas
337580

COL
Caqueta
108574


DECLARE @colnameList varchar(200)

SET @colnameList = NULL
SELECT @colnameList = COALESCE(@colnameList + ',','') + DISTRICT
FROM CITY;

DECLARE @SQLQuery NVARCHAR(MAX)

SET @SQLQuery ='
SELECT *
FROM (
	SELECT l.COUNTRYCODE, l.DISTRICT, l.POPULATION
	FROM dbo.CITY l
) t 
PIVOT (
	MAX(POPULATION)
	FOR DISTRICT IN ('+@colnameList+') 
) p;
'

EXEC(@SQLQuery)


COUNTRYCODE
Curacao
Catamarca
Cayo
Caldas
Chaco
Caqueta


ANT
2345
null
null
null
null
null

ARG
null
134935
null
null
229212
null

BLZ
null
null
7105
null
null
null

COL
null
null
null
337580
null
108574

COUNTRYCODE	Curacao	Catamarca	Cayo	Caldas	Chaco	Caqueta
ANT	2345	null	null	null	null	null
ARG	null	134935	null	null	229212	null
BLZ	null	null	7105	null	null	null
COL	null	null	null	337580	null	108574