초보적인 질문입니다.

​<nav id="gnb">        <h2>메인메뉴</h2>        <ul id="gnb_1dul">            <?php            $sql = " select *                        from {$g5['menu_table']}                        where me_use = '1'                          and length(me_code) = '2'                        order by me_order, me_id ";            $result = sql_query($sql, false);            $gnb_zindex = 999; // gnb_1dli z-index 값 설정용             for ($i=0; $row=sql_fetch_array($result); $i++) {            ?>            <li class="gnb_1dli" style="z-index:<?php echo $gnb_zindex--; ?>">                <a href="<?php echo $row['me_link']; ?>" target="_<?php echo $row['me_target']; ?>" class="gnb_1da"><?php echo $row['me_name'] ?></a>                <?php                $sql2 = " select *                            from {$g5['menu_table']}                            where me_use = '1'                              and length(me_code) = '4'                              and substring(me_code, 1, 2) = '{$row['me_code']}'                            order by me_order, me_id ";                $result2 = sql_query($sql2);                 for ($k=0; $row2=sql_fetch_array($result2); $k++) {                    if($k == 0)                        echo '<ul class="gnb_2dul">'.PHP_EOL;                ?>                    <li class="gnb_2dli"><a href="<?php echo $row2['me_link']; ?>" target="_<?php echo $row2['me_target']; ?>" class="gnb_2da"><?php echo $row2['me_name'] ?></a></li>                <?php                }                 if($k > 0)                    echo '</ul>'.PHP_EOL;                ?>            </li>            <?php            }             if ($i == 0) {  ?>                <li id="gnb_empty">메뉴 준비 중입니다.<?php if ($is_admin) { ?> <br><a href="<?php echo G5_ADMIN_URL; ?>/menu_list.php">관리자모드 &gt; 환경설정 &gt; 메뉴설정</a>에서 설정하실 수 있습니다.<?php } ?></li>            <?php } ?>        </ul>    </nav>