I'm trying to select and echo a single field.
This is my code when I'm trying it
session_start();
$query = "select id from user where username = ".$_SESSION['username'];
$result = mysql_query($query);
$admin_id = mysql_fetch_array($result);
echo $admin_id['id'];
When I run that code, this warning text appears
mysql_fetch_array() expects parameter 1 to be resource, boolean given in ......
How should I do it?
You should use quotes when you assign values in sql queries .
$query = "select id from user where username = '{$_SESSION['username']}'";
Or
$query = "select id from user where username = '" . $_SESSION['username'] . "'";
However, it is not a good practice so you better look forward prepared statements to reduce sql injection vulnerability : http://ru2.php.net/pdo.prepared-statements
Try this:
$username = $_SESSION['username'];
$query = "select id from user where username = '$username'";