Admin panel - Creating an edit users button - html

Question

I've created an admin panel on my website so when the admin logs in he can edit users. I'm trying to get it to create a table that displays a list of all the users on the database, however, when I run it I get the error:
No database selected
Here is the code in my editusers.php:
<?php
include 'adminpage.php';
include 'connection.php';
$sql = "SELECT * FROM Users";
$result = mysql_query($sql)or die(mysql_error());
echo "<table>";
echo "<tr><th>UserID</th><th>First Name</th><th>Last Name</th><th>Email</th><th>D-O-B</th></tr>Username</th><th>Password</th><th>";
while($row = mysql_fetch_array($result)){
$userid = $row['UserID'];
$firstname = $row['FirstName'];
$lastname = $row['LastName'];
$email = $row['Email'];
$dob = $row['DateofBirth'];
$username = $row['Username'];
$password = $row['Password'];
// Now for each looped row
echo "<tr><td style='width: 200px;'>".$userid."</td><td style='width: 200px;'>".$firstname."</td><td>".$scale."</td><td>".$lastname."</td><td>".$email."</td></tr>".$dob."</td></tr>".$username."</td></tr>".$password."</td></tr>";
} // End our while loop
echo "</table>"
?>

Answer 1

First of all it looks like you are using mysql which isn't a wise move. This is because Mysql is actually deprecated and was improved to mysqli. Your problem may be to do with your database connection. You also haven't set a database. Like I said you can set an active database in your connection script. It should or could look something like this.
<?php
$conn = mysqli_connect("localhost", "root", "password", "database");
// Evaluate the connection
if (mysqli_connect_errno()) {
echo mysqli_connect_error();
exit();
}
?>
After that, your sql query is correct by selecting all from you table 'users' but in order to proceed I recommend creating a query where you use mysqli_query an select the $sql and $conn as parameters. In all honesty it is much advised to stop and continue once you have adapted to mysqli. Alternatively you can use PDO which in some cases can be seen as better to use rather than mysqli but the choice is yours. I personally would get to grips with mysqli and then look at some answers on Stack Overflow to decide whether you should use PDO or not. Visit the PHP manual here. Enter all the mysql functions you know and it will show you how to use the new mysqli version of the functions. Don't think that it is as simple as just adding and 'i' to the end of a mysql function. That's what I initially thought but there is alot to do with extra parameters etc. Hope this helps :-)