public function prevnext($table,$id,$where=[]){

$ids=db($table)->field('id,title')->order('sort asc')->where($where)->column('id');

$key=array_search($id,$ids);

// 上一条

if(isset($ids[$key-1])){

$prevnext['prev']=db($table)->field('id,title,country_id')->where('id',$ids[$key-1])->find();

}else{

$prevnext['prev']=false;

}

if(isset($ids[$key+1])){

$prevnext['next']=db($table)->field('id,title,country_id')->where('id',$ids[$key+1])->find();

}else{

$prevnext['next']=false;

}

return $prevnext;

}