MySQL क्लोजर टेबल पदानुक्रमित डेटाबेस - सही क्रम में जानकारी को कैसे खींचें

Question

मेरे पास क्लोजर टेबल विधि का उपयोग कर एक MySQL डेटाबेस पदानुक्रमित डेटा है। स्क्रिप्ट बनाने वाला एक सरल नमूना डेटाबेस प्रश्न का पालन करता है। इस समय मेरी समस्या यह है कि मैं सही क्रम में डेटाबेस से डेटा कैसे खींचूं? मैं वर्तमान में निम्नलिखित चयन कथन का उपयोग कर रहा हूं।

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` 

यह सही जानकारी खींचता है लेकिन सही क्रम में नहीं।

नमूना डेटाबेस नमूना डेटा के साथ स्क्रिप्ट बनाते हैं।

-- 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   | 
+----+--------------+---------------------+-----+----------+------------+-------------+