在php（3php脚本）中使用Session变量for循环，并使用Excel工作表的表单复选框

<?php
session_start(); 
 // $filename = "Report_" . date('MmDY') . ".xls";
 // header("Content-type: application/octet-stream");
 // header("Content-Disposition: attachment; filename=\"$filename\"");  
 // header("Pragma: no-cache");
 // header("Expires: 0");

include ('../connection.php');
include ('../libchart/classes/libchart.php');

$calendarDate1 = $_SESSION['dateCalendarONE'];
$calendarDate2 = $_SESSION['dateCalendarTWO'];  
$inputValue = $_SESSION['menuInputVALUE'];

   $sql = ("
SELECT *
FROM `tally`, `category`
WHERE tally.catid = category.catid AND
date BETWEEN '" . $calendarDate1 . "' AND '" . $calendarDate2 . "'
        AND CATLABEL='" . $inputValue . "'
GROUP BY `catlabel`
");
 $rec = mysql_query($sql) or die (mysql_error());

$num_fields = mysql_num_fields($rec);

//loop count
for($i = 0; $i < $num_fields; $i++ )
{
    $header .= mysql_field_name($rec,$i)."\t";
}
//Oraganize information on the database.
while($row = mysql_fetch_assoc($rec))
{

    $line = '';
    foreach($row as $brotocol)
    {                                            
        if((!isset($brotocol)) || ($brotocol == ""))
        {
            $brotocol = "\t";
        }
        else
        {
            $brotocol = str_replace( '"' , '""' , $brotocol );
            $brotocol = '"' . $brotocol . '"' . "\t";
        }
        $line .= $brotocol;
    }
    $data .= trim( $line ) . "
";
}

$data = str_replace("" , "" , $data);

if ($data == "")
{
    $data = "
 BROTOCOL_ERROR: contact support!!!
";                        
}

print "$header
$data";
?>

When the session variable is passed, the exporting for excel is not looping through the and only reading 1 row. but When the sql statement is hard-coded in, it loops through as many rows as needed. Is the error with the loop alogrithm? or do I have to add another while loop in the code?