SELECT s1.*, s2.*, s3.*
FROM sections s1
  RIGHT JOIN sections s2 ON s2.parent_id = s1.section_id
  RIGHT JOIN sections s3 ON s3.parent_id = s2.section_id
  RIGHT JOIN sections s4 ON s4.parent_id = s3.section_id
WHERE s1.section_id = 1;

CREATE TABLE mp_tree (
    `id` BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `name` VARCHAR(50) NOT NULL,
    `path` VARCHAR(100) NOT NULL
) TYPE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE ns_tree (
    `id` BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `name` VARCHAR(50) NOT NULL,
    `lft` BIGINT NOT NULL,
    `rgt` BIGINT NOT NULL,
    `level` BIGINT NOT NULL
) TYPE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE al_tree (
    `id` BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `parent_id` BIGINT NULL,
    `name` VARCHAR(50) NOT NULL
) TYPE=InnoDB DEFAULT CHARSET=utf8;

CREATE PROCEDURE get_sections_in_parent`(IN inParentId INT(11))
BEGIN
    DECLARE ids MEDIUMTEXT DEFAULT '';

    SET @parents = inParentId;

    REPEAT
        SET ids = CONCAT(ids, IF(LENGTH(ids), ',', ''), @parents);
        
        SET @stm = CONCAT(
            'SELECT GROUP_CONCAT(section_id) INTO @parents 
             FROM sections 
             WHERE parent_id IN (', @parents, ')'
        );

        PREPARE fetch_childs FROM @stm;
        EXECUTE fetch_childs;
        DROP PREPARE fetch_childs;

    UNTIL (@parents IS NULL) END REPEAT;
    
    SET @stm = CONCAT (
        'SELECT *
        FROM sections
        WHERE section_id IN (', ids, ')'
    );

    PREPARE statement FROM @stm;
    EXECUTE statement ;
    DROP PREPARE statement;
END$$