问如何在smarty模板引擎中实现嵌套的foreach循环？

EN

$result = mysqli_query($conn,"SELECT * FROM subCategory ");
$list_subchannels = array();
while ( $row = mysqli_fetch_assoc($result) )
{

        $subcategory = $row['subcat_id'];
        $result1 = mysqli_query($conn,"SELECT * FROM member JOIN subCategory ON member.subcategory_id = subCategory.subcat_id WHERE member.subcategory_id = '$subcategory' ");
        $list_subchannels = array();
        while ( $row1 = mysqli_fetch_assoc($result1) )
        {
            $list_subchannels[] = $row1;
            $smarty->assign($row1['subcat_name'],$list_subchannels);

        }


        $list_subcategories[] = $row;
        $smarty->assign("subcategory",$list_subcategories);

}

{foreach from=$subcategory key=k item=b}
    Sub Category Names: {$b.subcat_name}

    <!-- Listing Item -->
    {foreach from=$b.subcat_name key=k item=a}
                    <h3>Member Name: {$a.channel_name}</h3>
                    <span>Member Id: {$a.member_id}</span>
    {/foreach}                
    <!-- Listing Item / End -->

{/foreach}