我真的对laravel关系感到惊讶，因为它给出的结果没有重复的条目，而如果与左连接比较的话。例如，最近我尝试了self-join，将多个连接到同一个表

public function parentMenu(){
        return $this->hasMany(Page::class,'parent_page_id','id');
    }

并返回以下结果

Array
(
    [0] => Array
        (
            [id] => 1
            [page_name] => Branch Details
            [page_url] => #
            [parent_page_id] => 0
            [page_type] => 1
            [created_at] => 2018-06-23 23:45:34
            [updated_at] => 2018-06-23 23:45:34
            [deleted_at] => 
            [slug] => branch_detail
            [parent_menu] => Array
                (
                    [0] => Array
                        (
                            [id] => 2
                            [page_name] => Add Branch Detail
                            [page_url] => add-branch
                            [parent_page_id] => 1
                            [page_type] => 1
                            [created_at] => 2018-06-23 23:45:54
                            [updated_at] => 2018-06-23 23:45:54
                            [deleted_at] => 
                            [slug] => add_branch_detail
                        )
                    [1] => Array
                        (
                            [id] => 11
                            [page_name] => View Branch Detail
                            [page_url] => list-branch
                            [parent_page_id] => 1
                            [page_type] => 1
                            [created_at] => 2018-06-23 23:46:08
                            [updated_at] => 2018-06-23 23:46:08
                            [deleted_at] => 
                            [slug] => 
                        )
                )
        )

我也试着找出问题所在

Array
(
    [0] => Array
        (
            [query] => select * from `pages` where `pages`.`deleted_at` is null
            [bindings] => Array
                (
                )
            [time] => 0.82
        )
    [1] => Array
        (
            [query] => select * from `pages` where `pages`.`parent_page_id` in (?, ?, ?, ?, ?, ?, ?, ?, ?, ?) and `pages`.`deleted_at` is null
            [bindings] => Array
                (
                    [0] => 1
                    [1] => 2
                    [2] => 4
                    [3] => 5
                    [4] => 7
                    [5] => 8
                    [6] => 9
                    [7] => 10
                    [8] => 11
                    [9] => 12
                )
            [time] => 0.86
        )
)

现在我的问题是，如果我尝试得到相同的结果，那么mysql查询将是什么呢？它将在内部执行forloop还是在查询本身中生成结果。
它还会在循环中执行单独的查询来检索子菜单列表吗？