Php 我怎么能只在拉威尔的“hasManyThrough”关系中挑出一个专栏呢？

“字段列表”中的未知列“user\u through\u building.id”（SQL:选择“user\u through\u building”。“id”来自'buildings'，其中'id'=20和'buildings'。“deleted\u at'为空）

试试这个

Building::with('user_through_building')
                      ->where('id', $building_id)
                      ->pluck('user_through_building.id');

试试这个

Building::with('user_through_building')
                      ->where('id', $building_id)
                      ->pluck('user_through_building.id');

// Retrieve all buildings that have at least one user_through_building
return Building::has('user_through_building')->get(['id']);

// Returns all Buildings, along with user_through_building' IDs
return Building::with('user_through_building:id')->get();