我如何从刀片视图中与 FK 连接的 3 个表中获取价值

Question

表：项目 enter image description here

表：projects_departmentsenter image description here 表：部门enter image description here

这是示范项目

public function projects_departments() {
    return $this->hasMany(Project_department::class); 
}

这是模型项目_部门

public function projects()
{
    return $this->belongsTo(Project::class);
}

public function departments()
{
    return $this->belongsTo(Department::class);
}

这里是模特部

public function projects()
{
    return $this->hasMany(Project::class);
}

public function projects_departments() {
    return $this->hasMany(Project_department::class); 
}

这是我的刀

project->departments->department_name

这是我的错误 SQLSTATE [42S22]：未找到列：1054 'where 子句'中的未知列'projects_departments.project_id'（SQL：select * from projects_departments where projects_departments.project_id = 48 和 projects_departments.project_id 是不为空）

Answer 1

$project = DB::table('projects')
        ->select(*)
        ->join('Department', 'projects_departments.department_id', '=', 'Department.id')
        ->join('projects_departments', 'projects_departments.project_id', '=', 'projects.id')

        ->get();

让我们试试这个