从一个不属于其他两个表的表中访问数据

Question

//示例数据库

最初的学者有1,2,3,4,5,6个ids

Scholar      
Id      
1   
2
3
4
5
6

现在，1和2是在表成员下进行的

Member 
Id
1 - taken
2 - taken

接下来的3和4是在表AddRequest下进行的

AddRequest
Id
3 - taken
4 - taken

现在，学者表应该只有我想要显示的i 5和6。

如何使用下面的代码解决此问题

public function ListOrgaScholar($ship_id)
{
    $members = Member::where('ship_id','=',$ship_id)->get();
    $members = $members->toArray();
    $scholar_ids = array_pluck($members, 'scholar_id');
    $scholar_exits = Scholar::whereNotIn('scholar_id', $scholar_ids)->get();

    $requests = AddRequest::where('ship_id','=',$ship_id)->get();
    $requests = $requests->toArray();
    $scholar_ids = array_pluck($requests, 'scholar_id');
    $add_exits = Scholar::whereNotIn('scholar_id', $scholar_ids)->get();   

    if ($scholar_exits == true && $add_exits == true) {

    $scholars = (new Scholar)->newQuery()->select('*');

    $scholars = $scholars->get();
    dd($scholars);
}else{
}
}

dd的结果

Collection {#302 ▼
  #items: array:7 [▼
    0 => Scholar {#305 ▶}
    1 => Scholar {#306 ▶}
    2 => Scholar {#307 ▶}
    3 => Scholar {#308 ▶}
    4 => Scholar {#309 ▶}
    5 => Scholar {#310 ▶}
    6 => Scholar {#311 ▶}
  ]
}

This for Member and AddRequest Table

This for Scholar

Answer 1

在对学者成员和addRequests进行了所有检查之后，您正在尝试从学者表中选择所有内容，这就是为什么您将获得所有六条记录的原因。

我会向scholar表中添加两个字段，比如is-member和has-request，并根据- is-member becomes true when the Scholar transitions to become a member和has-request becomes true when the Scholar add a request之类的事件将布尔值更新为true。因此，很容易找到既不是会员也没有任何要求的学者。

然而，对于您的情况，我认为您应该尝试如下所示：

public function ListOrgaScholar($ship_id)
{
    $scholar_ids = [];
    $members = Member::where('ship_id','=',$ship_id)->get();
    //$members = $members->toArray();
    //$scholar_ids = array_pluck($members, 'scholar_id');
    //$scholar_exits = Scholar::whereNotIn('scholar_id', $scholar_ids)->get();
    foreach($members as $member){
        $scholar_ids[] = $member->scholar_id;
    }

    $requests = AddRequest::where('ship_id','=',$ship_id)->get();
    //$requests = $requests->toArray();
    //$request_scholar_ids = array_pluck($requests, 'scholar_id');
    //$add_exits = Scholar::whereNotIn('scholar_id', $scholar_ids)->get();
    foreach($requests as $request){
        $scholar_ids[] = $request->scholar_id;
    }   

    $scholars = Scholar::whereNoIn('scholar_id', $scholar_ids)->get();
    dd($scholars);
}