将PHP变量值与MySQL列值进行比较

Question

I receive a post and want to do some actions only if the value of variable received in post exists in a specific column of the table. So i did this:

$pedidoID = $_POST["pedidoID"];
$con = mysql_connect("127.0.0.1", "root", "password") or die("Could not connect: " . mysql_error());
$result = mysql_query('SELECT id FROM listapagamento WHERE numeroPedido = "pedidoID"');
if(mysql_num_rows($result) == 0) {
//Some actions
}

So if the value from pedidoID doesn't exist in the column numeroPedido it will do the actions, because result will be 0 (because no rows are found).

What is happenning is that the $result is returning as bool(false) in both cases (if the value exists or not). I guess that my problem is how I'm using the variable inside the SELECT to compare to the column. I've tried to insert $_POST["pedidoID"] inside the SELECT also but my syntax was also wrong.

Does anyone know the correct syntax to use?

Answer 1

Try:

$pedidoID = mysql_real_escape_string($_POST["pedidoID"]);
$con = mysql_connect("127.0.0.1", "root", "password") or die("Could not connect: " . mysql_error());
mysql_select_db('<your_database_name>', $con);
$result = mysql_query("SELECT id FROM listapagamento WHERE numeroPedido = 'pedidoID'");
if(mysql_num_rows($result) == 0) {
//Some actions
}