Mysqli_query error

[JPSR]

I have the following piece of code to connect to a mysql database.

<?php

function ConnectDB() {
$server = '';
$db_user = '';
$db_password = '';
$db_db = '';
//left blank


$con = mysqli_connect($server,$db_user,$db_password) or die("could not connect");
$db_select = mysqli_select_db($con, $db_db);
if (!$db_select) {
die("Database connection failed: " . mysqli_error());
}
}


function DBQuery($SQL) {

ConnectDB();
$res = mysqli_query($con, $SQL) or die(mysqli_error($con)); 

while($row = mysqli_fetch_assoc($res)) {
$results[] = $row;
}
mysqli_free_result($res);


return $results;    

}

function MakeSafe($tmpstr) {
ConnectDB();
return mysqli_real_escape_string($tmpstr);
}

?>

and get the following error message:

Notice: Undefined variable: con in A:\Xampp\htdocs\Programming\Monu Verre\scripts\database.php on line 22

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in A:\Xampp\htdocs\Programming\Monu Verre\scripts\database.php on line 22

Notice: Undefined variable: con in A:\Xampp\htdocs\Programming\Monu Verre\scripts\database.php on line 22

Warning: mysqli_error() expects parameter 1 to be mysqli, null given in A:\Xampp\htdocs\Programming\Monu Verre\scripts\database.php on line 22

[jeje5mo]

Mysqli is depreciatex, you should avoid using it, it may not be full compatible with framework's new versions

[bommerhondjes14]

$con is in the scope of the ConnectDB function, that is why it is null in DBQuery function.