MySQL 8.0

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CREATE TABLE `test` (
    `id` INT,
    `countryCode` VARCHAR(50),
    `state` VARCHAR(50)
)  ENGINE=INNODB DEFAULT CHARSET=UTF8MB4 COLLATE = UTF8MB4_0900_AI_CI;
insert into `test` values 
(1,'AE','AE'),
(2,'SA','SA'),
(3,NULL,'SA') ;
SELECT 'id|countryCode|state|' AS `line` 
UNION ALL 
SELECT CONCAT_WS('|', `id`, COALESCE(`countryCode`, ''), COALESCE(`state`, '')) AS `line`
FROM `test`;


line


id|countryCode|state|

1|AE|AE

2|SA|SA

3||SA