php 查询二个时间段然后导出excel怎么做，新手

function exportExcel($data_array,$keynames,$filename) {
        //组合表头行,以制表符\t分隔,并转码为gb18030
        $title = implode ( "\t", array_values ( $keynames ) );
        $title = iconv ( "UTF-8", "GB18030", $title );
        
        $result [] = $title;
        //组合表体行
        foreach ( $data_array as $data ) {
            //按行组合数据体
            $a1 = array ();
            foreach ( $keynames as $k => $v ) {
                if ($k == "time") {
                    $data [$k] = date ( "Y-m-d", $data [$k] );
                }
                //utf8转码到gb18030,为了windows正常显示
                $a1 [] = iconv ( "UTF-8", "GB18030", preg_replace ( "/[\t]+/", " ", $data [$k] ) );
            }
            //以制表符分隔每列gb2312
            $result [] = implode ( "\t", $a1 );
        }
        
        //为了windows下正常显示,以\r\n为换行符,分隔数据字符串
        $result = implode ( "\r\n", $result );
        header ( "Content-type: text/html; charset=GB18030" );
        header ( "Content-Disposition: attachment; filename=\"" . $filename . ".xls\"" );
        exit ( $result );
    }