Q:

PHP Variable in Select Statement

I've written this PHP-Script which is working, and now I want to change the row name into a variable to (not sure if row is correct), I mean the "name" from the select name...
I've tried nearly everything, but nothing gave me the right result.
I know that the normal thing how I can use variables in a statement like ("'. $var .'") won't work.
<?php
require_once 'config.php';

$id = $_GET["id"]; //ID OF THE CURRENT CONTACT
$user = $_GET["user"];  //ID OF THE CURRENT USERS

$query = mysql_query("SELECT name FROM contacts WHERE contact_id='". mysql_real_escape_string( $id ) ."' and user_id='1';");

$retval = mysql_fetch_object($query)->name;

$retval = trim($retval);
echo $retval;
?>

A:

This is much easier isn't it?
$sql_insert = 
"INSERT INTO customers (        
`name`,
`address`,
`email`,
`phone`
) 
VALUES (        
'$name',
'$address',     
'$email',
'$phone'
)";

A:

Is it this you're looking for? Even your question in German isn't that clear to me :
$field = 'name';
$query = mysql_query("SELECT $field FROM contacts WHERE contact_id='". mysql_real_escape_string( $id ) ."' and user_id='1';");
$retval = mysql_fetch_object($query)->$field;

A:

You can usi it something like this. Currently i assume you get only one row back and want to use only one field.
<?php
require_once 'config.php';

$id = $_GET["id"]; //ID DES DERZEITIGEN KONTAKTES
$user = $_GET["user"];  //ID DES DERZEITIGEN USERS

//Use variable inside closures `` and just in case escape it, depends how you get variable
$query = mysql_query("SELECT `".mysql_real_escape_string($variable)."` FROM contacts WHERE contact_id='". mysql_real_escape_string( $id ) ."' and user_id='1';");

if (!$query) {
    echo 'Could not run query: ' . mysql_error();
    exit;
}
$row = mysql_fetch_row($query); //Retriev first row, with multiple rows use mysql_fetch_assoc
$retval = $row['0']; //Retriev first field

$retval = trim($retval); 
echo $retval;
?>

