MySQLi查询到Excel生成两个空行

Question

I am trying to generate excel file for my dynamic query using below codes.

$cname = $_POST["cname"];
        $cnote = $_POST["cnote"];
        $ccondition = $_POST['sql'];
        $crange = $_POST['start'] . "-" . $_POST['end'];
        $sql_query = $ccondition;

        $filename = "export".date('Ymd') . ".xls";
        header("Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        header("Content-Disposition: attachment; filename=\"$filename\"");
        $show_coloumn = false;

        $resultset = mysqli_query($mysqli, $sql_query) or die("database error:". mysqli_error($mysqli));

        $rowcount=mysqli_num_rows($resultset);

        $developer_records = array();
        while( $rows = mysqli_fetch_assoc($resultset) ) {
        $developer_records[] = $rows;
        }   

        if(!empty($developer_records)) {
            foreach($developer_records as $record) {
                if(!$show_coloumn) {

                    echo implode("\t", array_keys($record)) . "
";
                    $show_coloumn = true;
                }
                echo implode("\t", array_values($record)) . "
";
            }
        }

I am facing two issue in it. 1) When I try to open it in excel 2016, its giving error like below but when I press yes its opening file. 2) each my exported excel file have two blank row on top before header row, I don't know from where its coming and how I can fix it.

I have searched lot for it but I have not found any working solution for it. Let me know if someone can help me for solve the issues. Thanks