php - Mysqli 查询在服务器中不工作并且在本地运行正常

Question

我不明白这里发生了什么。这是我的代码:

    <?php
function chestnum(){
  $servername = "localhost";
  $username = "athletics";
  $password = "";
  $dbname = "athletics";
  // Create connection
  $conn = mysqli_connect($servername, $username, $password, $dbname);
  // Check connection
  if (!$conn) {
      die("Connection failed: " . mysqli_connect_error());
  }
  //selecting all chest number unallotted students
  $query = 'SELECT * FROM student WHERE CHEST = 0';
  $result = mysqli_query($conn, $query);
  //selecting all departments' max chest number
  //$query = 'SELECT MAX(CHEST) FROM student GROUP BY batch';
  //$max = mysqli_query($conn, $query);
  while($row = mysqli_fetch_assoc($result)){
    $batch = $row['batch'];
    $roll =  $row['roll'];
    $q = "SELECT MAX(`CHEST`) FROM `STUDENT` WHERE `batch`='$batch'";
    //$q = "SELECT MAX(CHEST) WHERE batch = $batch";
    $allmax = mysqli_query($conn, $q);
    while($rowm = mysqli_fetch_assoc($allmax))
     {
         echo $max=$rowm['MAX(`CHEST`)'];
     }
     //echo $cse = $bcr;echo $csa = $bcr;echo $me = $bcr; echo $ece = $bcr;echo $eee = $bcr;
/*
  CHEST NUMBER ALLOCATION INFO
  //100-250mech, 251-400ec, 401-550eee, 551-700cse, 701-850csa
*/
    //Checking for the department and setting chest number
    if($batch==1 && $max==0){
      $q = "UPDATE student SET CHEST = 100 WHERE roll LIKE '$roll'";
    } else if($batch==1 && $max == 250) {
      $q = "UPDATE student SET CHEST = 900 WHERE roll LIKE '$roll'";
    } else if($batch==1){
      $max++;
      $q = "UPDATE student SET CHEST = $max WHERE roll LIKE '$roll'";
    }
    if($batch==2 && $max==0){
      $q = "UPDATE student SET CHEST = 251 WHERE roll LIKE '$roll'";
    } else if($batch==2 && $max == 400) {
      $q = "UPDATE student SET CHEST = 1000 WHERE roll LIKE '$roll'";
    } else if($batch==2) {
      $max++;
      $q = "UPDATE student SET CHEST = $max WHERE roll LIKE '$roll'";
    }
    if($batch==3 && $max==0){
      $q = "UPDATE student SET CHEST = 401 WHERE roll LIKE '$roll'";
    }  else if($batch==3 && $max == 550) {
      $q = "UPDATE student SET CHEST = 1100 WHERE roll LIKE '$roll'";
    } else if($batch==3) {
      $max++;
      $q = "UPDATE student SET CHEST = $max WHERE roll LIKE '$roll'";
    }
    if($batch==4 && $max==0){
      $q = "UPDATE student SET CHEST = 551 WHERE roll LIKE '$roll'";
    } else if($batch==4 && $max == 700) {
      $q = "UPDATE student SET CHEST = 1200 WHERE roll LIKE '$roll'";
    } else if($batch==4) {
      $max++;
      $q = "UPDATE student SET CHEST = $max WHERE roll LIKE '$roll'";
    }
    if($batch==5 && $max==0){
      $q = "UPDATE student SET CHEST = 701 WHERE roll LIKE '$roll'";
    } else if($batch==5 && $max == 850) {
      $q = "UPDATE student SET CHEST = 1300 WHERE roll LIKE '$roll'";
    } else if($batch==5) {
      $max++;
      $q = "UPDATE student SET CHEST = $max WHERE roll LIKE '$roll'";
    }
    //assigning the chest number
    mysqli_query($conn, $q);
  }
}
?>

代码在我的本地机器上测试时运行良好，但在服务器上执行时却什么也没有显示。执行时没有报错。从另一个文件调用函数 chestnum。

Answer 1

这可能是显而易见的，但如果您还没有这样做，请更改您的服务器名称。如果它在本地主机上工作，那是因为您的服务器名称是本地主机。在你的网站上，转到你的控制面板并找到 mysql 区域，它会给你你应该使用的服务器名称，尽管它可能被称为主机名。将其复制到您拥有本地主机的位置。数据库名称也可能不同，但它会列在您的网络服务器控制面板上。