Question

我还是PHP的新手，我正在尝试使用PHP从MySQL检索数据。我有一个存储在csv文件中的id列表（csv的第一列）。所以我试图根据该ID检索数据。

//MySQL Connection
$con=mysqli_connect($hostname,$username,$password,$dbName);

//CSV File
$file_handle = fopen($fileName, "r");

$sql = "SELECT count(*) AS total FROM user WHERE user_id = ";

$i = 0;
while ($i < 50) {

    //Retrieving user_id from csv file
    $file_line = fgetcsv($file_handle, 1024);
    $query = $sql . $file_line[0];

    //Retrieving data from mySQL
    $result = mysqli_query($con,$query);   

    //Tested with single row but still giving me an error
    //$row = $result->fetch_assoc();
    $row = mysqli_fetch_array($result);
    echo $row;

    $i++;
}

 //close file
 fclose($file_handle);

 //close the connection
mysqli_close($con);

?>

我收到的错误消息：

 Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in C:\wamp\www\.. on line 59

所以，我不确定我做错了什么。任何帮助都会很棒。

更新：

感谢大家的帮助，我能够找出问题所在。这是我所做的更新代码。

$i = 0;
while ($i < 50) {

    //Retrieving user_id from csv file
    $file_line = fgetcsv($file_handle, 1024);
    $user_id = $file_line[0];

    $sql = "SELECT count(*) AS total FROM user WHERE user_id = $user_id ";

    //Retrieving data from mySQL
    $result = mysqli_query($con,$sql);   

    //Tested with single row but still giving me an error
    $row = mysqli_fetch_array($result);
    echo $row[0]; //Since this is an array I forgot to retrieve the first index of the array.

    $i++;
}

Answer 1

几乎是对的，你只需要改变：

$row = mysqli_fetch_array($result);

要：

$row = $result->fetch_array(MYSQLI_NUM);

或者只是这样做：

$row = mysqli_fetch_array($result, MYSQLI_NUM);

您必须指定结果类型。

Answer 2

我想你忘了在这里添加一些变量

$sql = "SELECT count(*) AS total FROM user WHERE user_id = ";

通常就像这样

$sql = "SELECT count(*) AS total FROM user WHERE user_id = " $userId = $file_line[0] "";

有关详细信息，请参阅this。这完全是关于 WHERE 条款，我认为这对你很有帮助。

无法使用PHP从MySQL检索行

2 个答案: