老实说，我不完全理解您的问题，您应该提供输出代码的结构.但是正如您的函数 getDataAsBinaryTree 所建议的那样，您正在尝试创建一个二叉树，如果是这种情况，这就是要走的路.

Honestly, I don't understand your question completely, you should provide the structure of output code. But as your function getDataAsBinaryTree suggests you're trying to make a binary tree, if that's the case then this is the way to go.

public function getDataAsBinaryTree($id = false){

    // $this->db->where('uid', $id);
    $query  = $this->db->get('binary_tbl');
    $result = [];

    if ($query->num_rows() > 0) {
        foreach ($query->result() as $k) {
            $result[$k->name] =  $this->tolevels($k->uid);
        }
    } else {
       $result = NULL;
    }
    // return $result;
    echo '<pre>'; print_r($result);  
}

private function tolevels($id){

    $this->db->where('supermember', $id);

    $query  = $this->db->get('binary_tbl');
    $output = [];
    $count  = $query->num_rows();

    if ($query->num_rows() > 0) {
        foreach ($query->result() as $key) {
            // $output[$key->name] = ($count > 0) ? $this->tolevels($key->uid) : $key->uid;
            $output[$key->name] = $key->uid;
            if($count > 0){ $this->tolevels($key->uid); };
        }
    } 
    return $output;
}

输出

Array
(
    [A] => Array
        (
            [B] => 2
            [C] => 3
        )

    [B] => Array
        (
            [D] => 4
        )

    [C] => Array
        (
            [E] => 5
            [G] => 6
        )

    [D] => Array
        (
            [H] => 7
            [I] => 8
        )

    [E] => Array
        (
        )

    [G] => Array
        (
        )

    [H] => Array
        (
            [J] => 9
        )

    [I] => Array
        (
        )

    [J] => Array
        (
        )

)

希望，这对您有帮助.:)

Hope, this helps you. :)