question about php and sql

[Carbine]

The above method is correct, although it would be better to use the mysql COUNT() function.

I'm just happy I got it right And I haven't quite got round to using the COUNT function yet, I'd rather research it first than just use it and hope for the best And I cba to research it atm

[ta2shop]

thanks guys, it is working now with carabine's method, lock:

<?php
$connect = mysql_connect("localhost","root","") or die(mysql_error());
mysql_select_db("ta2shop") or die(mysql_error());
 
// form data
$postal = $_POST['postal'];
$random = 'TA2_'.rand(0123456789,9876543210);
$date = date("Y-m-d");
 
if (isset($_POST['generate'])) {
        if($_POST['postal']) {
          $check = mysql_query("SELECT postal_code FROM postal_codes WHERE '$postal'=postal");
          $numrows = mysql_num_rows($check);
          if ($numrows!=1)
            echo"Postal code has already been used";
          else {
             $query = mysql_query("INSERT INTO postal_codes VALUES('','$postal','$random','$date')") or die(mysql_error());
             echo "<center>Success, your tracker ID is:".$random."</center>";
          }
        }
        else echo "<center>You must provide a postal code!</center>";
}
?>

but now sql prints this:

Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in C:\xampp\htdocs\trabajos\ta2shop - tienda\administracion\postal-code\index.php on line 46

[Carbine]

Check the query in the '$check' variable and change it to your database details. I didn't know what the fields were, but there is something wrong with the query and that's most likely it.

[jacek]

WHERE '$postal'=postal

This doesn’t look right to me

[jacek]

I was thinking more of

WHERE `postal` = '$postal_code'

Unsure on the column names though

[Carbine]

I was thinking more of

WHERE `postal` = '$postal_code'

Unsure on the column names though

The other way round works on my scripts
And it would be

WHERE 'postal_code' = '$postal'

If you look at the query in the above post by him that looks right.

[ta2shop]

it is ok, it worck now with no errors.
now i will meke the final check , i hope! the check to see if it is < then 13 or > then 13.
thanks for the help.