问题描述

我有一个 mysql 查询，我正在将其转换为 mysqli(准备好的语句)，但遇到了一个问题，引发了以下错误，

I had a mysql query and I was converting it to mysqli(prepared statement) but I ran in to a problem which throws the below error,

警告:mysqli_stmt::bind_result():绑定变量的数量与准备好的语句中的字段数量不匹配

Warning: mysqli_stmt::bind_result(): Number of bind variables doesn't match number of fields in prepared statement

Mysql 代码

$random_name_generated = vpb_generate_random_name().'.jpg'; //Generated name for uploaded files or images

if (move_uploaded_file($_FILES['file_to_upload']['tmp_name'], $final_uploads_location)) {
    $check_empty_field = mysql_query("select * from `vpb_uploads` where `username` = '".mysql_real_escape_string(strip_tags($username))."'  and `firstname` = '".mysql_real_escape_string("")."' and `lastname` = '".mysql_real_escape_string("")."'");
    if (mysql_num_rows($check_empty_field) < 1) {
        mysql_query("insert into `vpb_uploads` values('', '".mysql_real_escape_string($username)."', '', '', '".mysql_real_escape_string($random_name_generated)."', '', '', '', '', '".mysql_real_escape_string(date("d-m-Y"))."')");

        $identity = "image_one";
    } else {
        $get_empty_field = mysql_fetch_array($check_empty_field);
        $image_one = strip_tags($get_empty_field["image_one"]);
        $image_two = strip_tags($get_empty_field["image_two"]);
        $image_three = strip_tags($get_empty_field["image_three"]);
        $image_four = strip_tags($get_empty_field["image_four"]);
        $image_five = strip_tags($get_empty_field["image_five"]);
        global $identity;

以下是我尝试过的，即使它不起作用.我已经知道它行不通，但我想在提问之前自己尝试一下.错误来自 $get_empty_field = $stmt->bind_result($stmt);

The below is what I tried even though it didn't work. I already knew it won't work but I wanted to try it myself before asking a question. And the error is coming from the $get_empty_field = $stmt->bind_result($stmt);

if (move_uploaded_file($_FILES['file_to_upload']['tmp_name'], $final_uploads_location)) {
    $firstname = '""';
    $lastname = '""';
    $stmt = $mysqli->prepare("select * from `vpb_uploads` where `username` = ?  and `firstname` = ? and `lastname` = ?");
    $stmt->bind_param('sss', $username, $firstname, $lastname);
    $stmt->execute();
    $stmt->store_result();
    if ($stmt->num_rows < 1) {
        $date = 'date("d-m-Y")';
        $image_2 = "''";
        $image_3 = "''";
        $image_4 = "''";
        $image_5 = "''";
        $stmt = $mysqli->prepare("insert into `vpb_uploads` (`username`, `firstname`, `lastname`, `image_one`, `image_two`, `image_three`, `image_four`, `image_five`, `date`) values(?,?,?,?,?,?,?,?,?)");
        $stmt->bind_param('sssssssss', $username, $firstname, $lastname, $random_name_generated, $image_2, $image_3, $image_4, $image_5, $date);
        $stmt->execute();
        $stmt->close();

        $identity = "image_one";
    } else {
        $get_empty_field = $stmt->bind_result($stmt);
        $image_one = strip_tags($get_empty_field["image_one"]);
        $image_two = strip_tags($get_empty_field["image_two"]);
        $image_three = strip_tags($get_empty_field["image_three"]);
        $image_four = strip_tags($get_empty_field["image_four"]);
        $image_five = strip_tags($get_empty_field["image_five"]);
        global $identity;

推荐答案

你需要改变

$get_empty_field = $stmt->bind_result($stmt);

到

$get_empty_field = $stmt->bind_result($field1, $field2, $field3);

$fieldx 变量的数量等于所选字段的数量.如果你不知道有多少，使用这个:

The number of $fieldx variables being equal to the number of fields that are selected. If you don't know how many there are, use this:

  // Throw an exception if the result metadata cannot be retrieved
  if (!$meta = $stmt->result_metadata())
  {
    throw new Exception($stmt->error);
  }

  // The data array
  $data = array();

  // The references array
  $refs = array();

  // Iterate over the fields and set a reference
  while ($name = $meta->fetch_field())
  {
    $refs[] =& $data[$name->name];
  }

  // Free the metadata result
  $meta->free_result();

  // Throw an exception if the result cannot be bound
  if (!call_user_func_array(array($stmt, 'bind_result'), $refs))
  {
    throw new Exception($stmt->error);
  }

然后在获取后访问结果，使用 $data['field'];

And then you access the result, after fetching, with $data['field'];

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