无法获取数据

Question

我正在尝试获取我的数据库文件，该文件格式为 csv（excel 文件），但它甚至没有将数据发送到浏览器。

我还没有尝试过，因为我害怕我会做得比现在更糟......

我的 PHP 代码（我已经连接到数据库，但我不想公开显示我的信息）：

<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

// Create connection
$db = new mysqli($dbhost, $dbusername, $dbpassword, $dbname);

$allData = "";
$query = 'SELECT * FROM members';
  $retval = mysqli_query( $db,$query );
   if(! $retval ) {
      die('Could not get data.');
   }
   while($row = mysqli_fetch_array($retval)) {
  $allData .= $row['Id'] . ',' . $row['Email'] . ',' . $row['Condition'] .     ',' . $row['isEmailConfirmed'] . ',' . $row['Name'] . ',' .         $row['LastName'] . ',' . $row['Token'] . ',' .$row['Type'] . ',' .         $row['extra_privileges'] . ',' . $row['access-to-ftp'] . ',' .$row['access-    to-panel'] . ',' . $row['Birthdate'] . ',' . $row['Password'] . ',' .     $row['Description'] . "\n";
  //$retval = "data:text/csv;charset=utf-    8,ID,EMAIL,CONDITION,ISEMAILCONFIRMED,NAME,LASTNAME,TOKEN,TYPE,EXTRA_PRIVIL    EGES,ACCESS-TO-FTP,ACCESS-TO-PANEL,BIRTHDATE,PASSWORD,DESCRIPTION\n";
  $retval .= $allData;

  echo $retval;
  }
?>

它只是告诉我无法获取数据，我将其作为一个死解决方案。

Answer 1

您的问题是您正在重复使用相同的变量并且您正在丢失您的数据库结果。

$sql = 'SELECT * FROM members';
$retval = mysqli_query($db, $sql);
// ^^^^ This PHP variable holds your DB results
if (!$retval) {
    die('Could not get data.');
}
//  Each iteration of the loop you reach for a single row from the result $retval
while ($row = mysqli_fetch_array($retval)) {
    $allData .= $row['Id'] . ',' . $row['Email'] . ',' . $row['Condition']     . ',' . $row['isEmailConfirmed'] . ',' . $row['Name'] . ',' .     $row['LastName'] . ',' . $row['Token'] . ',' .$row['Type'] . ',' .     $row['extra_pivileges'] . ',' . $row['access-to-ftp'] . ',' .$row['access-to    panel'] . ',' . $row['Birthdate'] . ',' . $row['Password'] . ',' .     $row['Description'] . "\n";
    $retval = "data:text/csv;charset=utf-8,ID,EMAIL,CONDITION,ISEMAILCONFIRMED,NAME,LASTNAME,TOKEN,TYPE,EXTRA_PRIVILEG    ES,ACCESS-TO-FTP,ACCESS-TO-PANEL,BIRTHDATE,PASSWORD,DESCRIPTION\n";
    $retval .= $allData;
    // ^^^ but here you are using the same variable, thus losing its previous contents. 

    echo $retval;
}

更改您的 PHP 结果的名称，不要覆盖它。例如：

$sql = 'SELECT * FROM members';
$result_of_DB_select = mysqli_query($db, $sql);
// ^^^^ This PHP variable holds your DB results
if (!$result_of_DB_select) {
    die('Could not get data.');
}

// CSV header before the loop:
$CSV_response = "data:text/csv;charset=utf-8,ID,EMAIL,CONDITION,ISEMAILCONFIRMED,NAME,LASTNAME,TOKEN,TYPE,EXTRA_PRIVILEG    ES,ACCESS-TO-FTP,ACCESS-TO-PANEL,BIRTHDATE,PASSWORD,DESCRIPTION\n";

//  Each iteration of the loop you reach for a single row from the result variable called $result_of_DB_select 
while ($row = mysqli_fetch_array($result_of_DB_select)) {
    $CSV_response .= $row['Id'] . ',' . $row['Email'] . ',' . $row['Condition']     . ',' . $row['isEmailConfirmed'] . ',' . $row['Name'] . ',' .     $row['LastName'] . ',' . $row['Token'] . ',' .$row['Type'] . ',' .     $row['extra_pivileges'] . ',' . $row['access-to-ftp'] . ',' .$row['access-to    panel'] . ',' . $row['Birthdate'] . ',' . $row['Password'] . ',' .     $row['Description'] . "\n";
    // ^^^ different variable holds your CSV response now and you will not lose contents of $result_of_DB_select. 
}
echo $CSV_response;