Format date in MySQL SELECT as ISO 8601

This worked for me

DATE_FORMAT( CONVERT_TZ(`timestamp`, @@session.time_zone, '+00:00')  ,'%Y-%m-%dT%TZ')

The DATE_FORMAT(DateColumn) has to be in the SELECT list:

SELECT DATE_FORMAT(date, '%Y-%m-%dT%TZ') AS date_formatted
FROM table_name 
ORDER BY id DESC