Hierarchiczna baza danych MySQL Closure Table - Jak wyciągnąć informacje we właściwej kolejności

Question

Mam bazę danych MySQL przechowującą dane hierarchiczne przy użyciu metody tabeli zamykającej. Prosty przykładowy skrypt tworzenia bazy danych podąża za pytaniem. W tej chwili moim problemem jest jak wyciągnąć dane z bazy danych w prawidłowej kolejności? Obecnie używam poniższej instrukcji select.

SELECT `TreeData`.`iD`, `TreeData`.`subsectionOf`, 
     CONCAT(REPEAT('-', `TreePaths`.`len`),`TreeData`.`name`), 
     `TreePaths`.`len`,`TreePaths`.`ancestor`,`TreePaths`.`descendant` 
FROM `TreeData` 
LEFT JOIN `TreePaths` ON `TreeData`.`iD` = `TreePaths`.`descendant` 
WHERE `TreePaths`.`ancestor` = 1 
ORDER BY `TreeData`.`subsectionOrder` 

Wyciąga prawidłowe informacje, ale nie we właściwej kolejności.

Przykładowa baza danych tworzy skrypt z przykładowymi danymi.

-- Simple Sample 
SET FOREIGN_KEY_CHECKS=0; 
DROP TRIGGER IF EXISTS Tree_Insert; 
DROP TRIGGER IF EXISTS Tree_Update; 
DROP TABLE IF EXISTS TreePaths; 
DROP TABLE IF EXISTS TreeData; 
SET FOREIGN_KEY_CHECKS=1; 


CREATE TABLE `TreeData` (
    `iD`    INT NOT NULL,    -- PK 
    `subsectionOf` INT,      -- Parent ID & FK 
    `subsectionOrder` INT,      -- Oder of Subsections 
    `name`   NVARCHAR(500) NOT NULL, -- Name for the entry 
    PRIMARY KEY (`iD`), 
    FOREIGN KEY (`subsectionOf`) REFERENCES TreeData(`iD`) ON DELETE CASCADE, 
    INDEX(`name`) 
) ENGINE = MYISAM; 

-- Trigger to update the EntryPaths table for new entries 
DELIMITER // 
CREATE TRIGGER `Tree_Insert` AFTER INSERT ON `TreeData` FOR EACH ROW 
BEGIN 
    INSERT INTO `TreePaths` (`ancestor`, `descendant`, `len`) 
     SELECT `ancestor`, NEW.`iD`, len + 1 FROM `TreePaths` 
      WHERE `descendant` = NEW.`subsectionOf` 
      UNION ALL SELECT NEW.`iD`, NEW.`iD`, 0; 
END; // 
DELIMITER ; 


DELIMITER // 
CREATE TRIGGER `Tree_Update` BEFORE UPDATE ON `TreeData` FOR EACH ROW 
BEGIN 
    -- From http://www.mysqlperformanceblog.com/2011/02/14/moving-subtrees-in-closure-table/ 
    IF OLD.`subsectionOf` != NEW.`subsectionOf` THEN 
     -- Remove the node from its current parent 
     DELETE a FROM `TreePaths` AS a 
     JOIN `TreePaths` AS d ON a.`descendant` = d.`descendant` 
     LEFT JOIN `TreePaths` AS x 
     ON x.`ancestor` = d.`ancestor` AND x.`descendant` = a.`ancestor` 
     WHERE d.`ancestor` = OLD.`iD` AND x.`ancestor` IS NULL; 

     -- Add the node to its new parent 
     INSERT `TreePaths` (`ancestor`, `descendant`, `len`) 
     SELECT supertree.`ancestor`, subtree.`descendant`, supertree.`len`+subtree.`len`+1 
     FROM `TreePaths` AS supertree JOIN `TreePaths` AS subtree 
     WHERE subtree.`ancestor` = OLD.`iD` 
     AND supertree.`descendant` = NEW.`subsectionOf`; 
    END IF; 
END; // 
DELIMITER ; 


CREATE TABLE `TreePaths` (
    `ancestor`  INT NOT NULL, 
    `descendant` INT NOT NULL, 
    `len`   INT NOT NULL, 
    PRIMARY KEY (`ancestor`, `descendant`), 
    FOREIGN KEY (`ancestor`) REFERENCES TreeData(`iD`) ON DELETE CASCADE, 
    FOREIGN KEY (`descendant`) REFERENCES TreeData(`iD`) ON DELETE CASCADE 
) ENGINE = MYISAM; 

INSERT INTO `TreeData` VALUES(1, NULL, NULL, 'Root A'); 
INSERT INTO `TreeData` VALUES(2, 1, 1, 'Item 1'); 
INSERT INTO `TreeData` VALUES(3, 1, 2, 'Item 2'); 
INSERT INTO `TreeData` VALUES(4, 1, 3, 'Item 3'); 
INSERT INTO `TreeData` VALUES(5, 2, 2, 'Item 1 Sub Item 2'); 
INSERT INTO `TreeData` VALUES(6, 2, 1, 'Item 1 Sub Item 1'); 
INSERT INTO `TreeData` VALUES(7, 1, 3, 'Item 4'); 
INSERT INTO `TreeData` VALUES(8, 4, 1, 'Item 3 Sub Item 1'); 
INSERT INTO `TreeData` VALUES(9, 4, 2, 'Item 3 Sub Item 2'); 
INSERT INTO `TreeData` VALUES(10, NULL, NULL, 'Root B'); 
INSERT INTO `TreeData` VALUES(11, 10, 1, 'Item A'); 
INSERT INTO `TreeData` VALUES(12, 10, 2, 'Item B'); 
INSERT INTO `TreeData` VALUES(13, 10, 3, 'Item C'); 

Answer 1

SELECT d.`iD`, d.`subsectionOf`, 
     CONCAT(REPEAT('-', p.`len`), d.`name`) as hier, 
     p.`len`, p.`ancestor`, p.`descendant`, 
     GROUP_CONCAT(crumbs.`ancestor`) AS breadcrumbs 
FROM `TreeData` AS d 
JOIN `TreePaths` AS p ON d.`iD` = p.`descendant` 
JOIN `TreePaths` AS crumbs ON crumbs.`descendant` = p.`descendant` 
WHERE p.`ancestor` = 1 
GROUP BY d.`iD` 
ORDER BY breadcrumbs; 

+----+--------------+---------------------+-----+----------+------------+-------------+ 
| iD | subsectionOf | hier    | len | ancestor | descendant | breadcrumbs | 
+----+--------------+---------------------+-----+----------+------------+-------------+ 
| 1 |   NULL | Root A    | 0 |  1 |   1 | 1   | 
| 2 |   1 | -Item 1    | 1 |  1 |   2 | 1,2   | 
| 5 |   2 | --Item 1 Sub Item 2 | 2 |  1 |   5 | 1,2,5  | 
| 6 |   2 | --Item 1 Sub Item 1 | 2 |  1 |   6 | 1,2,6  | 
| 3 |   1 | -Item 2    | 1 |  1 |   3 | 1,3   | 
| 4 |   1 | -Item 3    | 1 |  1 |   4 | 1,4   | 
| 8 |   4 | --Item 3 Sub Item 1 | 2 |  1 |   8 | 1,4,8  | 
| 9 |   4 | --Item 3 Sub Item 2 | 2 |  1 |   9 | 1,4,9  | 
| 7 |   1 | -Item 4    | 1 |  1 |   7 | 1,7   | 
+----+--------------+---------------------+-----+----------+------------+-------------+