Question

我正在创建一个用户树，将其保存到.json文件中，但是我找不到在二级用户中读取第三方用户的方法

通过foreach，mysql的二级用户读了我，但未将它们对准第三位我的桌子是

1。（用户名= juan Referedby =无）

2。（（用户名= jose Referedby = juan）

3.（用户名= alberto所引用的= juan）

4.（用户名= fernando引用者= jose）

`` php


$stmt = $mysqli->prepare("SELECT username FROM affiliateuser WHERE referedby = '$actualuser'");
$stmt->execute();
$array = [];
foreach ($stmt->get_result() as $row)
{
    $referedby[] = $row['username'];

}
$string = '';
$string2 = '';
foreach ($referedby as $key => $secundaryusers){
}` ``

我希望结果能给我类似的东西。

    { "name": "juan ", "children": [ { "name ": "jose", "children": [{ "name": "fernando", "children": [] }] } { "name": "alberto", "children": [] } ] },

Answer 1

这里的想法是制作一个具有数据的PHP结构，该数据将存在于JSON中，然后使用json_encode（）将其转换为JSON。

如果您查看class User，则表示用户和所有后代。如果我可以用所有数据填充它，那么将其转换为JSON很容易。

请注意，表中的每个用户都有一个父级，存储在referredby_id列中。这是父用户的主键。如果需要，可以将其更改为用户名，只要保证表中的用户名是唯一的即可。为此，请将referredby_id列的类型更改为VARCHAR。如果数据量很大，请为用户名表建立索引。

表格：

CREATE TABLE `affilitateuser` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `username` varchar(40) DEFAULT NULL,
  `referredby_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

数据：

INSERT INTO `affilitateuser` (`id`, `username`, `referredby_id`) VALUES
(1, 'sarah', NULL),
(2, 'james', 1),
(3, 'tom', 2),
(4, 'natalie', 3),
(5, 'juan', NULL),
(6, 'jose', 5),
(7, 'alberto', 5),
(8, 'fernando', 5),
(9, 'camila', 8),
(10, 'sean', 9),
(11, 'scotty', 9),
(12, 'robert', 9),
(13, 'montgomery', 12),
(14, 'jessie', 13),
(15, 'cole', 13),
(16, 'cary', 14),
(17, 'porter', 14),
(18, 'sandra', 5),
(19, 'lily', 6);

代码：

// A class to represent nodes on a tree
class User
{
    public $name;
    public $children = [];
    public function __construct($name)
    {
        $this->name = $name;
    }
    // Add a child to this User
    public function addChild($name)
    {
        $u = new User($name);
        $this->children[] = $u;
        // return the newly created object so we can use it later.
        return $u;
    }
}

// Class that does the extracting
class UserTreeExtractor
{
    protected $conn; // keep the database connection

    public function run()
    {
        $this->connect();
        // Extract Juan's tree
        // print_r($this->tree(5));
        // Save the JSON to a string
        $jsonString = json_encode($this->tree(5), JSON_PRETTY_PRINT);
        // Write it out to a file
        file_put_contents('output.json', $jsonString);
    }
    // { "name": "juan ", "children": [ { "name ": "jose", "children": [{ "name": "fernando", "children": [] }] } { "name": "alberto", "children": [] } ] },

    /**
     * Gets the children and downstream descendants for a user
     */
    protected function tree($id)
    {
        // First, get the user
        $sql1 = "SELECT username FROM affilitateuser WHERE id = {$id}";
        $stmt = $this->conn->prepare($sql1);
        if ( ! $stmt ) {
            die('query failed');
        }
        $stmt->execute();
        $top = $stmt->get_result()->fetch_assoc();
        // print_r($top); exit();

        // Now get the all descendents
        $sql = "SELECT  id, username, referredby_id 
        FROM    (SELECT * FROM affilitateuser
        ORDER BY referredby_id, id) users_sorted,
        (SELECT @pv := '{$id}') initialisation
        WHERE   find_in_set(referredby_id, @pv)
        AND     LENGTH(@pv := CONCAT(@pv, ',', id))";
        // "SELECT username FROM `affiliateuser` WHERE referedby_id = {$id}"
        $stmt = $this->conn->prepare($sql);
        $stmt->execute();
        $children = [];
        $tree = new User($top['username']);
        // Keep an index of where the objects are stored
        // so we can find them later to attach their children.
        $index[$id] = $tree;
        $parent = null;
        foreach ($stmt->get_result() as $row)
        {
            if ( isset($index[$row['referredby_id']]) ) {
                $new = $index[$row['referredby_id']]->addChild($row['username']);
                $index[$row['id']] = $new; // put the new user into the index
            } else {
                // referred by some user that does not exist
                die("Referred by non-existent user");
            }
            $children[] = ['username' => $row['username'], 'id' => $row['id'], 'referredby_id' => $row['referredby_id']];
        }
        return $tree;
    }
    // Connect to the database
    protected function connect()
    {
        // Change the connection credentials as needed.
        $this->conn = mysqli_connect("127.0.0.1", "app", "aaaa", "sss"); 
        if( ! $this->conn ) { 
            die("Database Connection Failed: ".mysql_error()); 
        }
    }
}

$obj = new UserTreeExtractor;
$obj->run();

如何从foreach中获取确定值

1 个答案: