ca_id를 임시로 저장한후 2차로 변경한후 

마지막에 다시 임시 ca_id 를 재저장하는 방식으로 해보세요 

아래 추가 1,2 를 해보세요 

$ca_id_len = strlen($ca_id);
$len2 = $ca_id_len + 2;
$len4 = $ca_id_len + 4;

$sql = " select ca_id, ca_name from {$g5['g5_shop_category_table']} where ca_id like '$ca_id%' and length(ca_id) = $len2 and ca_use = '1' order by ca_order, ca_id ";
$result = sql_query($sql);
while ($row=sql_fetch_array($result)) {

    $row2 = sql_fetch(" select count(*) as cnt from {$g5['g5_shop_item_table']} where (ca_id like '{$row['ca_id']}%' or ca_id2 like '{$row['ca_id']}%' or ca_id3 like '{$row['ca_id']}%') and it_use = '1'  ");

    $str .= '<li><a href="./list.php?ca_id='.$row['ca_id'].'">'.$row['ca_name'].' ('.$row2['cnt'].')</a></li>';
    $exists = true;
}

을 

//----------------------------
//여기를 추가 해주세요 1
$ca_len=strlen($ca_id);
if($ca_len==8){
    $old_ca_id=$ca_id;
    $ca_id=substr($ca_id, 0, 6);
}
//----------------------------

$ca_id_len = strlen($ca_id);
$len2 = $ca_id_len + 2;
$len4 = $ca_id_len + 4;

$sql = " select ca_id, ca_name from {$g5['g5_shop_category_table']} where ca_id like '$ca_id%' and length(ca_id) = $len2 and ca_use = '1' order by ca_order, ca_id ";
$result = sql_query($sql);
while ($row=sql_fetch_array($result)) {

    $row2 = sql_fetch(" select count(*) as cnt from {$g5['g5_shop_item_table']} where (ca_id like '{$row['ca_id']}%' or ca_id2 like '{$row['ca_id']}%' or ca_id3 like '{$row['ca_id']}%') and it_use = '1'  ");

    //현재 위치는  active  로 처리 했습니다 
    $str .= '<li><a href="./list.php?ca_id='.$row['ca_id'].'" '.(($row[ca_id]==$old_ca_id)?"active":"").'>'.$row['ca_name'].' ('.$row2['cnt'].')</a></li>';
    $exists = true;
}

//----------------------------
//여기를 추가 해주세요 2
if($ca_len==8){
    $ca_id=$old_ca_id;
}
//----------------------------