各行のMySQLサブクエリルーピングが返される

Question

これは2つのクエリを使用し、2番目のクエリを実行する最初のサブクエリで返された各行の結果を取得するのが好きで、基本的にforeachループのように動作します。私はこれを非常に迅速に把握できる人がいることを願っています。

CREATE TABLE `File_Structure`(
    `id` INT PRIMARY KEY AUTO_INCREMENT, 
    `name` VARCHAR(255) NOT NULL DEFAULT '', 
    `is_folder` TINYINT(1) NOT NULL DEFAULT 0, 
    `lft` INT NOT NULL DEFAULT 0, 
    `rht` INT NOT NULL DEFAULT 0, 
    `is_active` TINYINT(1) NOT NULL DEFAULT 1, 
    `created` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP, 
    `modified` DATETIME NOT NULL DEFAULT '0000-00-00 00:00:00' 
)ENGINE=InnoDB; 
INSERT INTO `file_structure` (`id`, `name`, `is_folder`, `lft`, `rht`, `is_active`, `created`, `modified`) VALUES 
    (1, 'Code', 1, 1, 12, 1, '2017-11-26 00:13:40', '0000-00-00 00:00:00'), 
    (2, 'Account', 1, 2, 7, 1, '2017-11-26 00:13:40', '0000-00-00 00:00:00'), 
    (3, 'AccountCreate.php', 0, 3, 4, 1, '2017-11-26 00:13:40', '0000-00-00 00:00:00'), 
    (4, 'AccountsFindAll.php', 0, 5, 6, 1, '2017-11-26 00:13:40', '0000-00-00 00:00:00'), 
    (5, 'JournalEntry', 1, 8, 11, 1, '2017-11-26 00:13:41', '0000-00-00 00:00:00'), 
    (6, 'JournalCreate.php', 0, 9, 10, 1, '2017-11-26 00:13:41', '0000-00-00 00:00:00'); 

-- 1. FIND ALL LEAF NODES OF A DESIRED NODE. 
SELECT `name` 
FROM `File_Structure` AS `MAIN`, 
(
    SELECT `lft`, `rht` 
    FROM 
    `File_Structure` 
    WHERE `name`='Account' 
) AS `SUB` 
WHERE `MAIN`.`lft`>`SUB`.`lft` 
AND `MAIN`.`rht`<`SUB`.`rht` 
AND `MAIN`.`rht`=`MAIN`.`lft`+1 
; 
-- 2. FOR A LEAF NODE, GET A PATH UPTO THE DESIRED NODE. 
//SET group_concat_max_len = 2048 TO AVOID THE LIMIT OF 1K STRING LENGTH. 

SELECT GROUP_CONCAT(`SUB`.`name` SEPARATOR '/') AS `CONCATEDNAME` 
FROM 
(
    SELECT `PARENT`.`name` 
    FROM `File_Structure` AS `NODE`, 
    `File_Structure` AS `PARENT` 
    WHERE `NODE`.`lft` BETWEEN `PARENT`.`lft` AND `PARENT`.`rht` 
    AND `NODE`.`name` = 'AccountsFindAll.php' 
    ORDER BY `PARENT`.`lft` 
) AS `SUB` 
; 

-- 3. REPEAT 2 FOR 1 

Answer 1

それはサブクエリのさまざまなレベルよりもJOINを使用する方がはるかに簡単です：

SELECT GROUP_CONCAT(path.name ORDER BY path.lft SEPARATOR '/') AS CONCATEDNAME 
FROM File_Structure AS root 
JOIN File_Structure AS leaf ON leaf.lft BETWEEN root.lft AND root.rht 
JOIN File_Structure AS path ON leaf.lft BETWEEN path.lft AND path.rht 
WHERE leaf.rht = leaf.lft+1 
AND root.name='Account' 
GROUP BY leaf.name; 

出力：

+----------------------------------+ 
| CONCATEDNAME      | 
+----------------------------------+ 
| Code/Account/AccountCreate.php | 
| Code/Account/AccountsFindAll.php | 
+----------------------------------+