Laravel -直接抓取所有孙辈(或作为数组)

Question

我的模式的简化版本：

学生

• id

student_bursaries

• id
• student_id

student_bursary_enrolments

• id
• student_bursary_id

student_bursary_enrolments_courses

• id
• student_bursary_enrolment_id
• course

我想在学生模型上有一个公共功能，这样我就可以直接获取它的所有课程。

例：

$id = 80;
$student = Student::findOrFail($id);
$courses = $student->courses();

我试过这样的方法：

public function courses() {
    return $this
        ->join('student_bursaries','student_bursaries.student_id','=','students.id')
        ->join('student_bursary_enrolments','student_bursary_enrolments.student_bursary_id','=','student_bursaries.id')
        ->join('student_bursary_enrolment_courses','student_bursary_enrolment_courses.student_bursary_enrolment_id','=','student_bursary_enrolments.id')
        ->select('student_bursary_enrolment_courses.id','student_bursary_enrolment_courses.course');
}

但这只会返回“所有的课程”，而不是$this特有的课程--所以我必须给它传递一个id，这样就不符合"$this“的意思了。

这将是最终的解决方案，但我愿意走另一条路，做一些不属于模式的事情，比如：

$records = Student::with(['bursaries','bursaries.enrolments','bursaries.enrolments.courses'])->where('id',80)->get();

但是这会返回许多模型，我只想要一个当然名称和ID的列表，所以我尝试了以下方法，但是它没有工作：

学生：：带(“奖学金”，“助学金”，'bursaries.enrolments.courses')->where('id',80)->get()->pluck('bursaries.enrolments.courses.id'，'bursaries.enrolments.courses.course')；

结果：

$records = Student::with(['bursaries','bursaries.enrolments','bursaries.enrolments.courses'])->where('id',80)->get()->pluck('bursaries.enrolments.courses.id','bursaries.enrolments.courses.course');

=> Illuminate\Support\Collection {#10344
 all: [
   "" => null,
 ],

}

Answer 1

由于您需要将结果作为课程的集合，所以您应该从该模型开始。

public function courses() {
    return StudentBursaryEnrolmentsCourse::whereHas('enrolment', function($enrolment) {
        $enrolment->whereHas('bursary', function($bursary) {
            $bursary->where('student_id', $this->id);
        });
    })->get();
}

或者独立于上下文$this

$studentId = 80;
$courses = StudentBursaryEnrolmentsCourse::whereHas('enrolment', function($enrolment) use ($studentId) {
    $enrolment->whereHas('bursary', function($bursary) use ($studentId) {
        $bursary->where('student_id', $studentId);
    });
})->get();

这假设(您可以将它们更改为实际设置)：

课程类= StudentBursaryEnrolmentsCourse

• Enrolments关系
• 课程类=

您可以像这样在pluck()之前使用get()

$studentId = 80;
$courses = StudentBursaryEnrolmentsCourse::whereHas('enrolment', function($enrolment) use ($studentId) {
    $enrolment->whereHas('bursary', function($bursary) use ($studentId) {
        $bursary->where('student_id', $studentId);
    });
})->pluck('courses.id','course');