mysqli_num_rows() expects

[damiendarien]

trying to figure this problem out. sucks being a newbie maybe i will gain enough knowledge to be able to help out others in the near future.

<?php
session_start();

$DBConnect = @mysqli_connect("localhost", "**********", "**********")
Or die("<p>Unable to connect to the database server.</p>"
	. "<p>Error code " . mysqli_connect_errno()
	. ": " . mysqli_connect_error()) . "</p>";
$DBName = "skyward_aviation";
@mysqli_select_db($DBConnect, $DBName)
Or die("<p>Unable to select the database.</p>"
	. "<p>Error code " . mysqli_errno($DBConnect)
	. ": " . mysqli_error($DBConnect)) . "</p>";

$CustomerName = "";
if (isset($_COOKIE['customerName']))
$CustomerName = $_COOKIE['customerName'];

$TableName = "mileage";
$Mileage = 0;
$SQLstring = "SELECT SUM(mileage) FROM $TableName WHERE
flyerID='{$_SESSION['flyerID']}";
$QueryResult = @mysqli_query($DBConnect, $SQLstring);
if (mysqli_num_rows($QueryResult) > 0) {
		$Row = mysqli_fetch_row($QueryResult);
		$Mileage = number_format($Row[0], 0) ;
		mysqli_free_result($QueryResult);
}

mysqli_close($DBConnect);

?>

 

i know its a simple stupid error but cant remember nor figure it out. HERES THE ERROR

 

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in C:\xampp\htdocs\PHP_Projects\Chapter.10\FrequentFlyerClub.php on line 23

[objnoob]

For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning resultset, mysql_query() returns a resource on success, or FALSE on error.

 

Your result is a boolean on a select. This means you're receiving FALSE on an error.

 

Try adding a check to your $result variable as such:

 

$SQLstring = "SELECT SUM(mileage) FROM $TableName WHERE	flyerID='{$_SESSION['flyerID']}";
$QueryResult = @mysqli_query($DBConnect, $SQLstring);
if ($QueryResult === false){
   echo mysql_error($DBConnect);
}

 

 

I can tell you now, your missing a single quote at the end of your SQL statement.  flyerID='{$_SESSION['flyerID']}'";

 

 

[wildteen88]

You haven't constructed your query correctly. You have a missing ' at the end of your query

$SQLstring = "SELECT SUM(mileage) FROM $TableName WHERE

flyerID='{$_SESSION['flyerID']}'";

 

However you probably don't need to to have the quotes wrapped around {$_SESSION['flyerID']}. If that variable only contains numbers. Only strings should be wrapped in quotes.

[damiendarien]

Thanks both of you. That solved it. like i said i knew it would be something simple that i was overlooking. Thanks again.