Question

我正在为我的学校制作一个系统，让教师在内联网上发布他们当天的任何通知。我正在关注this教程，更改代码以满足我的需求，但是在测试时遇到了这个错误：

警告：mysqli_select_db（）预计在第15行的C：\ Users \ Matthew \ Desktop \ wamp64 \ www \ my-site \ addguestbook.php中只有2个参数，1。

以下是该页面的代码：

    <?php
$host="localhost"; // Host name 
$username="root"; // Mysql username 
$password=""; // Mysql password 
$db_name="test"; // Database name 
$tbl_name="guestbook"; // Table name 

// Connect to server and select database.
mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); 
mysqli_select_db("$db_name")or die("cannot select DB");

$datetime=date("y-m-d h:i:s"); //date time

$sql="INSERT INTO $tbl_name(name, email, comment, datetime)VALUES('$name', '$email', '$comment', '$datetime')";
$result=mysql_query($sql);

//check if query successful 
if($result){
echo "Successful";
echo "<BR>";

// link to view guestbook page
echo "<a href='viewguestbook.php'>View guestbook</a>";
}

else {
echo "ERROR";
}
mysql_close();
?>

注意：这与网站上同名的其他问题不同，因为它处于不同的情况。

Answer 1

你有一个使用对象和一个使用链接的可能性

使用链接：

$link = mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); 

mysqli_select_db($link, "$db_name")or die("cannot select DB");

$sql="INSERT INTO $tbl_name(name, email, comment, datetime)VALUES('$name', '$email', '$comment', '$datetime')";
$result = mysqli_query($link, $sql);
$row = mysqli_fetch_row($result);
mysqli_free_result($result);

mysqli_close($link);

对象：

$mysqli = mysqli("$host", "$username", "$password"); 

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

$mysqli->select_db("$db_name");

$sql="INSERT INTO $tbl_name(name, email, comment, datetime)VALUES('$name', '$email', '$comment', '$datetime')";
$result = $mysqli->query($sql);
$row = $result->fetch_row();
$result->close();

$mysqli->close();

详细说明here

Answer 2

而不是

// Connect to server and select database.
mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); 
mysqli_select_db("$db_name")or die("cannot select DB");

DO

// Connect to server and select database.
$db=mysqli_connect($host, $username, $password)or die("cannot connect server "); 
mysqli_select_db($db,$db_name)or die("cannot select DB");

Answer 3

尝试：

$link = mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); 
mysqli_select_db($link,"$db_name")or die("cannot select DB");

Answer 4

应该有2个参数，连接链接和数据库名称

$link = mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); 
mysqli_select_db($link, "$db_name")or die("cannot select DB");

你正在使用mysql与mysqli_ * *

$ sql =＆＃34; INSERT INTO $ tbl_name（姓名，电子邮件，评论， datetime）VALUES（＆＃39; $ name＆＃39;，＆＃39; $ email＆＃39;，＆＃39; $ comment＆＃39;，＆＃39; $ datetime＆＃39;）＆＃34 ;; $结果= mysql_query（$ SQL）;

＆安培;

mysql_close（）;

Answer 5

我希望它会对你有所帮助

  // Connect to server and select database.
$con=mysqli_connect("$host", "$username", "$password","$db_name")or         die("cannot connect server "); 


 $datetime=date("y-m-d h:i:s"); //date time
 $name="abc";
 $email="abc@gmail.com";
  $comment="posted";
  $sql="INSERT INTO $tbl_name(name, email, comment, datetime)VALUES('$name',  '$email', '$comment', '$datetime')";
 $result=mysqli_query($con,$sql);

 //check if query successful 
 if($result){
 echo "Successful";
 echo "<BR>";

 // link to view guestbook page
echo "<a href='viewguestbook.php'>View guestbook</a>";
 }

 else {
 echo "ERROR";
  }
 mysqli_close($con);
  ?>

Answer 6

你混合了mysqli和mysql，必须使用mysqli

试试这个

<?php
$host     = "localhost"; // Host name 
$username = "root"; // Mysql username 
$password = ""; // Mysql password 
$db_name  = "test"; // Database name 
$tbl_name = "guestbook"; // Table name 

$con      = mysqli_connect($host, $username, $password, $db_name);

// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

$datetime = date("y-m-d h:i:s"); //date time
$name     = 'Name here';
$email    = 'example@example.com';
$comment  = 'Comment here';

$sql    = "INSERT INTO $tbl_name (name, email, comment, datetime) VALUES ('$name', '$email', '$comment', '$datetime')";
$result = mysqli_query($con, $sql) or die("Error: ".mysqli_error($con));

//check if query successful 
if($result){
echo "Successful";
echo "<br>";

// link to view guestbook page
echo "<a href='viewguestbook.php'>View guestbook</a>";
}

else {
echo "ERROR";
}

mysqli_close($con);
?>

Answer 7

$ conn = mysqli_connect（$ host，$ username，$ password，$ db_name）;

$ sql =“INSERT INTO $ tbl_name（name，email，comment，datetime）VALUES（'$ name'，'$ email'，'$ comment'，'$ datetime'）”;

$ result = mysqli_query（$ conn，$ sql）;

警告：mysqli_select_db（）需要2个参数，给定1个

7 个答案: