how i insert 1 data with 2 string? and insert into database? - mysql

Question

i was doing a insert statement and i want 2 username become 1 data and insert into database. i no sure how to do it.
here is my php and mysql
$target = $_GET['user'];
$id = $_SESSION['id'];
$targetusername = mysqli_query($connection,"SELECT username FROM user WHERE id='$target' ")or die(mysqli_error($connection));
$username= mysqli_query($connection,"SELECT username FROM user WHERE id='$id'") or die(mysqli_error($connection));
$direct_message_room_name ="INSERT INTO direct_message_room(`direct_message_room_name`,`user_1_id`,`user_2_id`) VALUES (('$targetusername' + ' and ' + '$username'),'$id','$target')";

Answer 1

In order to have two variables in one column, you can serialize an array, though this is generally frowned upon unless it's for a good reason.
$array = array('username'=>'user1','username2'=>'user2');
$serialize = serialize($array);
Gives you:
a:2:{s:8:"username";s:5:"user1";s:9:"username2";s:5:"user2";}
Use the unserialize() function to return it to an array. Wordpress is one notable web application that stores arrays in such a way.
On a side note, you need to use bind parameter to avoid injectable sql queries:
// Do not do this
$target = $_GET['user'];
mysqli_query($connection,"SELECT username FROM user WHERE id='$target' ")
Here is a reference:
What does bind_param accomplish?

Answer 2

You can concat two strings in php like so:
$StringAB = $StringA . " something " . $StringB;
$target = $_GET['user'];
$id = $_SESSION['id'];
$targetusername = mysqli_query($connection,"SELECT username FROM user WHERE id='$target' ")or die(mysqli_error($connection));
$username= mysqli_query($connection,"SELECT username FROM user WHERE id='$id'") or die(mysqli_error($connection));
$rowUserName = mysql_fetch_array($username);
$rowTargetUserName = mysql_fetch_array($targetusername );
$room_name = $rowUserName["username"] . ' and ' . $rowTargetUserName["username"]; // Create room name (assuming both exist)
$direct_message_room_name ="INSERT INTO direct_message_room(`direct_message_room_name`,`user_1_id`,`user_2_id`) VALUES ('$room_name','$id','$target')";