PHP禁用round_up

How can I disable the round up in my PHP script. If I sum up something it only displays the rounded Number.

<?php

$con=mysqli_connect("localhost","XXXX","XXXX","XXXX");
if (mysqli_connect_errno()) {
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT * FROM energrid WHERE ID = 1 ");

while($row = mysqli_fetch_array($result)) {
    $wert = $row['Wert'];
}
$result = mysqli_query($con,"SELECT * FROM energrid WHERE ID = 3 ");

while($row = mysqli_fetch_array($result)) {
    $wert1 = $row['Wert'];
}
mysqli_close($con);
echo "here we go.:";
echo $wert + $wert1;
?>

Ok, I guess I've found my mistake. The values are like 3,5 with a , instead of a .

How can I change that if these are values directly from the MySQL DB.?

1.You can use number_format function
2.optimize your code -there is no need of while loop to do this

 <?php    
$db = mysql_connect("localhost","username","password");  ///connect to mysql      
if (!$db) {      
// throw error if not connect      
 die("Database connection failed miserably: " . mysql_error());      
        }          
$db_select = mysql_select_db("databasename",$db); ///select database      
if (!$db_select) {      
//database connection error      
die("Database selection also failed miserably: " . mysql_error());       
}      
$sum=0;       
$result = mysqli_query($db,"SELECT sum(wert) as sum FROM energrid WHERE ID in ('1','3') ");       
$row = mysqli_fetch_array($result)       
$sum =$row['sum'];       
`enter code here`      

echo number_format($sum,'number','.','');
//where number-no. of  place you want to round off 
?>

Try using a cast like this :

echo (int)$wert + (int)$wert1;
echo (float)$wert + (float)$wert1;

use str_replace() like this to replace the comma , in number by decimal point .

$a = "3,5";

str_replace(",",".",$a);