[RESOLVED] supplied argument is not a valid MySQL-Link Error

[Skor]

I'm receiving the error above in my shopping cart application. I sell one-off items and use Paypal as the payment engine. In the remote possibility an item was previously purchased I loop through each order and update one at a time. I'm counting rows so if a record is not updated, I'd like to know. Strangely, it's working as designed (sending emai), but don't want to deploy unless I know why this error is occuring.

Here's what I've got so far. Here's the full error:

1. Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in cartworks15.php on line 105.

2. Do I need to change the variable to a different function. Is my syntax correct.

Please let me know. Thanks in advance.

3. The code:

mysql_query ($query);

// breaks the string into an array of products
$products = explode("~", $cart);

$i = 0;

// breaks each product string into its own array
foreach($products as $var => $val){

  $product[$i] = explode(":", $val);
  $desc = $product[$i][0];
  $qty = $product[$i][1];
  $money = $product[$i][2];
  $pid = $product[$i][4];

$update = "UPDATE ckd_labinv SET status ='S',
  sold_code = 'COD', sold_date = NOW()
  WHERE pid = '$pid'
  and status = 'A'";
  mysql_query($update) or die(mysql_error());

  $i++;
}

//echo '...Updated Database <br>'; 

$to = "[e-mail]";
$subject = "Already Purchased Alert!";
$contents = "\nThe following item has already been purchased:\n\n * $desc \n\nThis item was purchased by the following customer:\n\n  $inv_name,$email, on $date.\n";
$from_header = "From: [e-mail]";
$num_rows = mysql_num_rows($update);  [COLOR="Red"][B]//offending line[/B][/COLOR]
//mysql_affected_rows($update);

 if ($num_rows == 0) 
 {
mail( $to, $subject, $contents, $from_header);
echo '...sent Already Purchased Alert <br>'; 
}

Thanks in advance.

[laserlight]

1. Check that the script connects to the database server.
2. Check that the database is selected.
3. Check that the associated query is correct.

[greensweater]

Update is a string, not a resource result

change:

mysql_query($update) or die(mysql_error());

to:

$result = mysql_query($update) or die (mysql_error());

and

$num_rows = mysql_num_rows($update);

to:

$num_rows = mysql_num_rows($result);

[Skor]

I tweaked your suggestion just a bit and got this sucker resolved. Thanks for putting me on the right path. I moved my if logic within the loop as well and that seemed to do the trick.:rolleyes:

[bradgrafelman]

Don't forget to mark this thread resolved.