php - 在 PHP 中使用 fetchAll 返回多个数组

Question

我正在尝试从数据库中检索多行。我遇到的问题是每次我使用这个函数时，它都会替换我已经尝试返回的所有其他行，并且它只返回最后一行。如果有人知道更好的方法或知道如何实际完成这项工作，请发表评论。

刚在这里发帖，如果这在某些方面不正确，我们深表歉意。谢谢。

我的代码:

public function getPosts($id){
        global $pdo;

        $query = $pdo->prepare("SELECT * FROM friends WHERE f1 = ? OR f2 = ?");
        $query->bindValue(1, $id);
        $query->bindValue(2, $id);
        $query->execute();
        $res = $query->fetchAll();
            foreach($res as $user):
                if($user['f1'] == $id):
                    $query = $pdo->prepare("SELECT * FROM posts JOIN users ON posts.user_id = users.id WHERE user_id = ?");
                    $query->bindValue(1, $user['f2']);
                    $query->execute();
                else:
                    $query = $pdo->prepare("SELECT * FROM posts JOIN users ON posts.user_id = users.id WHERE user_id = ?");
                    $query->bindValue(1, $user['f1']);
                    $query->execute();
                endif;

                return $query->fetchAll(); //Trying to return arrays.
            endforeach;


}

Answer 1

尝试这样的事情。我不知道 f1 和 f2 是什么，所以我只是将它们添加为占位符。我在这里没有使用bindValue。仅使用 array($f1_id, $f2_id) 调用执行更简单

public function getPosts($id){
    global $pdo;

    $f1_id = 1; //placeholder
    $f2_id = 2; //placeholder

    $posts = array();

    $stmt = $pdo->prepare("SELECT * FROM friends WHERE f1 = ? OR f2 = ?");
    $stmt->execute(array($f1_id, $f2_id));

    //Iterate over the friend records.
    //fetch() returns next record or false on failure (No more records).
    //false terminates the while loop.
    while($user = $stmt->fetch()) {
        if($user->f1 == $f1_id) :
            $stmt_post = $pdo->prepare("SELECT * FROM posts JOIN users ON posts.user_id = users.id WHERE user_id = ?");
            $stmt_post->execute(array($user['f2']));
        else:
            $stmt_post = $pdo->prepare("SELECT * FROM posts JOIN users ON posts.user_id = users.id WHERE user_id = ?");
            $stmt_post->execute(array($user->['f1']));
        endif;

        while($post = $stmt_post->fetch()) {
            $posts[] = $post; //"$posts[] = " syntax is used to append the $post to the array.
        }
    }

    return $posts;
}