PHP，从数据库中获取数据

Question

我想用 PHP 从数据库中检索数据并将其显示在网站上。

此代码无法正常工作。我想在我的数据库中显示所有雪佛兰汽车。

<?php
$db = mysqli_connect("localhost","myusername",
"mypassword","database");

if (mysqli_connect_errno()) { 
    echo("Could not connect" .
      mysqli_connect_error($db) . "</p>");
    exit(" ");
}

$result = mysqli_query($query);

if(!$result){
  echo "<p> Could not retrieve at this time, please come back soon</p>" .   
    mysqli_error($dv);
}

$data = mysql_query("SELECT * FROM cars where carType = 'Chevy' AND active = 1")
  or die(mysql_error());

echo"<table border cellpadding=3>";
while($row= mysql_fetch_array( $data ))
{
  echo"<tr>";
  echo"<th>Name:</th> <td>".$row['name'] . "</td> ";
  echo"<th>ImagePath:</th> <td>".$row['imagePath'] . " </td></tr>";
  echo"<th>Description:</th> <td>".$row['description'] . "</td> ";
  echo"<th>Price:</th> <td>".$row['Price'] . " </td></tr>";
}
echo"</table>";
?>

如何使用 PHP 从数据库中获取数据？

Answer 1

您没有查询数据库，所以它不会给您结果

它是这样工作的

1) 通过 mysql_connect() 连接到数据库

mysql_connect("localhost", "username", "password") or die(mysql_error()); 

2) 比选择像mysql_select_db() 这样的数据库

mysql_select_db("Database_Name") or die(mysql_error()); 

3) 你需要使用mysql_query()

喜欢

 $query = "SELECT * FROM cars where carType = 'chevy' AND active = 1";
 $result =mysql_query($query); //you can also use here or die(mysql_error()); 

查看是否出错

4) 比 mysql_fetch_array()

  if($result){
         while($row= mysql_fetch_array( $result )) {
             //result
        }
      }

那么试试

$data = mysql_query("SELECT * FROM cars where carType = 'chevy' AND active = 1")  or die(mysql_error()); 
 echo"<table border cellpadding=3>"; 
 while($row= mysql_fetch_array( $data )) 
 { 
    echo"<tr>"; 
    echo"<th>Name:</th> <td>".$row['name'] . "</td> "; 
    echo"<th>ImagePath:</th> <td>".$row['imagePath'] . " </td></tr>"; 
    echo"<th>Description:</th> <td>".$row['description'] . "</td> "; 
    echo"<th>Price:</th> <td>".$row['Price'] . " </td></tr>"; 
 } 
 echo"</table>"; 
 ?> 

注意:

Mysql_* 函数已弃用，因此请使用 PDO 或 MySQLi 代替。我建议 PDO 更容易阅读，您可以在这里学习 PDO Tutorial for MySQL Developers还要检查 Pdo for beginners ( why ? and how ?)