字段列表中的未知列$ cat_name

Question

I got the error: unknown column in field list, while I know for sure I haven't made any typos and the columns exist.

Anyone know what I'm overlooking?

<?php  
//create_cat.php  
include '../includes/connection.php';  


$cat_name = mysql_real_escape_string($_POST['cat_name']);
$cat_description = mysql_real_escape_string($_POST['cat_description']);


if($_SERVER['REQUEST_METHOD'] != 'POST')  
{  
    //the form hasn't been posted yet, display it  
    echo "<form method='post' action=''>  
        Category name: <input type='text' name='cat_name' id='cat_name'/>  
        Category description: <textarea name='cat_description' id='cat_description' /></textarea>  
        <input type='submit' value='Add category' />  
     </form>"; 
} 
else 
{ 
    //the form has been posted, so save it 
    $sql = 'INSERT INTO categories(cat_name, cat_description) VALUES ($cat_name, $cat_description)';  
    $result = mysql_query($sql);  
    if(!$result)  
    {  
        //something went wrong, display the error  
        echo 'Error' . mysql_error();  
    }  
    else  
    {  
        echo 'New category successfully added.';  
    }  
}  
?> 

Answer 1

Try this:

$sql = "INSERT INTO categories(cat_name, cat_description) VALUES ('$cat_name', '$cat_description')"; 

Update: You used ' to start a string. When doing this its not possible to use variables in the text, they will just be leaved as plain text. But when using " the variables will be evaluated.