Question

function __construct(mysqli $db, $country = NULL, $sport = NULL) {
    $this->db = $db;
    $this->country = base64_decode($country);
    $this->sport = base64_decode($sport);
}

public function GetColor($colorcode) {
    $query = 'SELECT naam_nl FROM colors WHERE code = $colorcode';
    $result = $this->db->query($query);
    while ($row = $result->fetch_assoc()) { // Line 21
        echo $row['naam_nl'];
    }
    $result->close();
}

给我：

Fatal error: Call to a member function fetch_assoc() on a non-object in /home/cloud/public/td/teamdresser.class.php on line 21

所以我试过了：

    $result = $this->db->query($query);
    while ($row = $this->db->fetch_assoc($result)) {
        echo $row['naam_nl'];
    }

然后......

Fatal error: Call to undefined method mysqli::fetch_assoc() in /home/cloud/public/td/teamdresser.class.php on line 21

我做错了什么..有人能指出我正确的方向吗？

Answer 1

这部分错了：

public function GetColor($colorcode) {
    $query = 'SELECT naam_nl FROM colors WHERE code = $colorcode';

使用单引号时，PHP不会插入$colorcode。使用双引号intead：

$query = "SELECT naam_nl FROM colors WHERE code = $colorcode";

<强>评论：

始终检查返回值！这使得发现错误变得更加容易。
为什么不使用准备好的陈述？

Answer 2

就像评论所说，你需要做一些错误检查：

public function GetColor($colorcode) {
    $query = 'SELECT naam_nl FROM colors WHERE code = $colorcode';
    $result = $this->db->query($query);
    if ($result === false) {
        // Throw or handle an error here
    } else {
        while ($row = $result->fetch_assoc()) { // Line 21
            echo $row['naam_nl'];
        }
        $result->close();
    }
}

此外，您还需要mysqlnd驱动程序：Fatal error: Call to undefined method mysqli_result::fetch_all()

在类中使用MySQLi

2 个答案: