PHP Variable in Select Statement - php

Question

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;
?>

Answer 1

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

Answer 2

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;

Answer 3

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;
?>

Answer 4

Please post in English. Everyone else does.
Try using a different fetch method - fetch an associative array, then use the dynamic parameter to retrieve whatever column it is you need.
Have you considered using PDO?

Answer 5

I believe you are confusing matters (unintentionally) due to your use of the word 'row'. Judging by your example you mean field/column. It sounds like you wish to specify the fields to select using a variable which can be done by any of these methods...
$fields = "name, age";
$sql = "SELECT $fields FROM table";
$sql = "SELECT {$fields} FROM table";
$sql = "SELECT ".$fields." FROM table";
NB it is important that you have secure date in the $fields element, I would suggest using a whitelist of allowed values i.e.
// assuming $_POST['fields'] looks something like array('name','age','hack');
$allowed = array('name', 'age');
$fields = array();
foreach ($_POST['fields'] as $field) {
if (in_array($field, $allowed)) {
$fields[] = $field;
}
$fields = implode(', ', $fields);

Answer 6

Wouldn't this work?
$result = mysql_fetch_array($query);
echo trim($result['name']);

Answer 7

You should never put a variable into field list.
If want a variable field name, select *
and then use your variable to fetch particular field
<?php
require_once 'config.php';
$id = mysql_real_escape_string($_GET["id"]); //ID DES DERZEITIGEN KONTAKTES
$user = $_GET["user"]; //ID DES DERZEITIGEN USERS
$query = "SELECT * FROM contacts WHERE contact_id='$id' and user_id='1'";
$result = mysql_query($query) or trigger_error(mysql_error().$query);
$row = mysql_fetch_array($result);
//and finally
$fieldname = "name";
$retval = $row[$fieldname];
echo $retval;
?>