MySql and PHP query - php

Question

I have a problem!
I need to get player_id knowing only the player name from one MySQL table with one php query.
My code is this:
$user = $_POST['user_search'];
$player_id = mysql_query("SELECT * FROM `".$prism_table_players."` WHERE player = '".$user."'");
$player_id_2 = mysql_fetch_array($player_id);
$player_id_3 = $player_id_2['player_id'];
I'm already connected to the MySQL database etc... I just need to get the player_id when I have only the player name.
If needed the table is structurated like this:
player_id player
3411 John
4012 Mark
I need to get the player_id when having just the player
For example I need to get 3411 when I send as html input the player "John"
Resolved guys, here the correct code for extract it:
$player_id = mysql_query("SELECT * FROM `".$prism_table_players."` WHERE player = '".$user."'");
$player_id_2 = mysql_fetch_row($player_id);
$player_id_3 = $player_id_2['0'];

Answer 1

First of all, you're application isn't safe. User input is directly put into query and this allows your user to destroy your database. Secondly, you're using mysql_* functions - it is not recommended, use mysqli_* or PDO instead. To get player_id from your array, you have to use:
$user = $_POST['user_search'];
$player_id = mysql_query("SELECT * FROM `".$prism_table_players."` WHERE player = '".$user."'");
$player_id_2 = mysql_fetch_row($player_id);
$player_id_3 = $player_id_2[0];
It would be better if you would use mysqli prepared statements.

Answer 2

You really should NOT use the mysql_* functions - they are deprecated. Use either MySQLi or PDO connection; I personally prefer PDO so I'll write this as PDO:
//just to demonstrate the connection part:
$dbh = new PDO("mysql:host=".DB_HOST.";dbname=".DB_NAME,DB_USER,DB_PASS);
//the important stuff
$stmt = $dbh->prepare("Select player_id from {$prism_table_players}
WHERE player = :player");
$stmt->execute(array("player" => $_POST['user_search']));
$entry = $stmt->fetch(PDO::FETCH_ASSOC);
$player_id = $entry['player_id'];

Answer 3

// try to execute below echo in phpmyadmin or mysql console
echo $query = "SELECT * FROM `".$prism_table_players."` WHERE player = '".$user."'"
$player_id = mysql_query($query);
You can use trim() for
$user = trim($_POST['user_search']);
or
// try to execute below echo in phpmyadmin or mysql console
echo $query = "SELECT * FROM `".$prism_table_players."` WHERE player LIKE '".$user."'"
$player_id = mysql_query($query);