这个例子是对课程进度表里面的某个学生的剩余课时进行求和汇总。
laravel 版本是 lts 5.5
StudentLessonProgress::where('student_info_id', $student_info_id)
->sum('total_left_class_num');
打印sql语句如下:
array:1 [▼
0 => array:3 [▼
“query” => “select sum(total_left_class_num) as aggregate from student_lesson_progress where student_info_id
1