DELETE FROM users WHERE id IN (
SELECT id FROM (
	SELECT * FROM users a
		LEFT JOIN
			(SELECT	Max(id) max_id FROM users GROUP BY duplic_col) b
		ON a.id = max_id
	WHERE max_id IS NULL
) AS select_id
);
-- Successfully Tested!
-- ------------------------------------------------------------------

DELETE a
FROM   users a
       LEFT JOIN(SELECT Max(date_col) max_date,
                        col_1,
                        col_2
                 FROM   users
                 GROUP  BY col_1,
                           col_2) b -- Select Max-Date for every group
              ON a.date_col = max_date -- Left join 'users' with Select Max-Date
                 AND a.col_1 = b.col_1
                 AND a.col_2 = b.col_2 -- Compare by another columns
WHERE  b.max_date IS NULL;             -- Where date_col != max_date
-- -------------------------------------------------------------------

DELETE FROM comments WHERE CommentId IN (
SELECT CommentId FROM
 	(SELECT * FROM comments a
 		LEFT JOIN
	(SELECT	Max(CommentId) max_id FROM comments GROUP BY CommentZendeskId ) b
 		ON a.CommentId = max_id
    WHERE a.CommentZendeskId != 0 AND b.max_id IS NULL
	AND CreatedAt >= '2019-05-21 11:20'
) AS x
);