Questions PHP

<?php
/**
 * Export MySQL data to an Excel spreadsheet
 * @param $query A MySQL Query
 * Usage : 
 *		$sql_query = mysql_query("SELECT * FROM examples");
 *		mysql_to_excel($sql_query);
 */
function mysql_to_excel($query)
{
	$export = $query;
	$count = mysql_num_fields($export);
	/************
	Extract field names and write them to the $header variable
	/***********/
	$header = excel_header($query);

	/***********
	Extract all data, format it, and assign to the $data variable
	/**********/
	$data = excel_append($query);

	/************
	Set the default message for zero records
	/************/
	if ($data == "")
	{
		$data = "\n(0) Records Found!\n";
	}
	
	/************
	Set the automatic download section
	/************/
	excel_compose($header, $data);
}

function excel_header($query)
{
	/*************
	Build query, call it, and find the number of fields
	/*************/
	$export = $query;
	$count = mysql_num_fields($export);
	
	/************
	Extract field names and write them to the $header variable
	/***********/
	for ($i = 0; $i < $count; $i++)
	{
		$header .= mysql_field_name($export, $i).";";
	}
	return $header;
}

function excel_append($query)
{
	/*************
	Build query, call it, and find the number of fields
	/*************/
	$export = $query;
	$count = mysql_num_fields($export);
	
	/************
	Extract field names and write them to the $header variable
	/***********/
	for ($i = 0; $i < $count; $i++)
	{
		$header .= mysql_field_name($export, $i).";";
	}
	
	/***********
	Extract all data, format it, and assign to the $data variable
	/**********/
	while($row = mysql_fetch_row($export))
	{
		$line = '';
		foreach($row as $value)
		{
			if ((!isset($value)) OR ($value == ""))
			{
				$value = ";";
			}
			else
			{
				$value = str_replace('"', '""', $value);
				$value = '"' . $value . '"' . ";";
			}
			$line .= $value;
		}
		$data .= trim($line)."\n";
	}
	$data = str_replace("\r", "", $data);
	return $data;
}

function excel_compose($header, $data)
{
	/************
	Set the automatic download section
	/************/
	header("Content-type: application/octet-stream");
	header("Content-Disposition: attachment; filename=spreadsheet.csv");
	//header("Content-Disposition: attachment; filename=".$_GET['t']."_".date("Ymd").".csv");
	header("Pragma: no-cache");
	header("Expires: 0");
	print "$header\n$data";
}
?>

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