//aps，building，square关联
$list = DB::table('aps')
->join('building','building.id', '=' ,'aps.building_id')
->join('square','square.id', '=' ,'aps.campus_id')
->join('sys_location_info','sys_location_info.location_id' ,'=', 'square.location_id')
->select('square.location_id','building.id as dev_code','building.building_name as dev_name','aps.mac as apmac')
->get();
if($list){
$lists = $list->toJson();
}else{
$lists ='';
}
return $lists;多表之间的关联查询
