我正在Laravel写查询,但它给了我错误说
ErrorException:类stdClass的对象无法转换为字符串
$subject_ids = DB::table('question_sets')
->select('subject_id')
->where('test_section_id','=',$testDetail->test_section_id)
->distinct()
->get();
$topic_ids = DB::table('topics')
->select('id')
->where('subject_id','=',$subject_ids)
->get();
在下面的查询中
$subject_ids = DB::table('question_sets')
->select('subject_id')
->where('test_section_id','=',$testDetail->test_section_id)
->distinct()->get();
你得到一个集合,如果你想要一个特定的价值,你可以使用first()
然后你可以做
$subject_id = DB::table('question_sets')
->select('subject_id')
->where('test_section_id','=',$testDetail->test_section_id)
->distinct()
->pluck('name')
->first();
和
$topic_ids = DB::table('topics')
->select('id')
->where('subject_id','=',$subject_id)
->get();
或者如果你想匹配所有$ subject_ids,你应该使用toArray()
和whereIn
之类的
$subject_ids = DB::table('question_sets')
->select('subject_id')
->where('test_section_id','=',$testDetail->test_section_id)
->distinct()
->pluck('subject_id')
->toArray();
和
$topic_ids = DB::table('topics')
->select('id')
->whereIn('subject_id', $subject_ids)
->get();