Help with Database Queries!

[Anon]

This is the code:

$Query = "SELECT SUM(is.Quantity), is.ExternalSKU, ";
$Query .= "SUM(is.Quantity * is.ListPrice) AS Subtotal, is.Freight ";
$Query .= "FROM invoice_sku is, sku s, item i ";
$Query .= "WHERE is.Invoice = " . $UserInfo['Invoice'] . " ";
$Query .= "AND is.SKU = s.ID ";
$Query .= "s.Item = i.ID ";
$Query .= "GROUP BY is.Invoice, is.Freight";
$DatabaseResult = mysql_query($Query, $DatabaseLink);
while($DatabaseRow = mysql_fetch_row($DatabaseResult))

{

                            $ShippingInfo[$DatabaseRow[3]]["Quantity"] = $DatabaseRow[0];               
                            $ShippingInfo[$DatabaseRow[3]]["ExternalSKU"] = $DatabaseRow[1];                  
                            $ShippingInfo[$DatabaseRow[3]]["Subtotal"] = $DatabaseRow[2];               
                            $ShippingInfo[$DatabaseRow[3]]["Freight"] = $DatabaseRow[3];              
                          /*
                            $ShippingInfo[$DatabaseRow[3]]["State"] = $shipAddress["StateProv"];        
                            $ShippingInfo[$DatabaseRow[3]]["Country"] = $shipAddress["CountryCode"];        
                          */

                            $ShippingInfo[$DatabaseRow[3]]["State"] = "NY";        
                            $ShippingInfo[$DatabaseRow[3]]["Country"] = "US";        
                    }

This is the error:
Warning: Supplied argument is not a valid MySQL result resource in /var/www/testing/php-3/php3/junk/date.php3 on line 20

What does the error mean? What am I doing wrong? How can I correct It?

Thanks in Advance

[Anon]

You haven't specified Country in the fields to select so it returns an error warning that the argument is not a valid results resource.

eg:

$Query = "SELECT SUM(is.Quantity), is.ExternalSKU, ";
$Query .= "SUM(is.Quantity is.ListPrice) AS Subtotal, is.Freight, is.Country"; /assuming that "is" is your table name */
$Query .= "FROM invoice_sku is, sku s, item i ";
$Query .= "WHERE is.Invoice = " . $UserInfo['Invoice'] . " ";
$Query .= "AND is.SKU = s.ID ";
$Query .= "s.Item = i.ID ";
$Query .= "GROUP BY is.Invoice, is.Freight";

[Anon]

The error usually means that your query could not be executed.
This can be because your query contians errors, or even because you are not connected to the database server at all.

Your code should include an if() statement to check if the query was executed properly.
If not, it should print the mysql error code like this:

echo mysql_errno().": ".mysql_error()."<BR>";

That will tell you things like "syntax error near blabla"

Also, you should print the sql statement that you are trying to execute,
so you can see where the error is exactly.

[Anon]

Nah, he's got the code that uses 'country' commented out.

Vincent's on the right track--you must never blindly use the
result of a query without testing it to see if it succeeded. In
this case, I think there's maybe a missing AND:

...
$Query .= "AND is.SKU = s.ID ";
$Query .= "s.Item = i.ID ";