查询数据 结果集逗号分割

$brandres = $db->select("select brand_id,brand_name from ecs_brand where $partamemter and is_show = 1 and brand_name like '%$keyword%'");
if(!empty($brandres)){
　　　　$brand_id = '';
　　foreach($brandres as $k => $v){
　　if($k){
　　　　$brand_id .= ",".$v->brand_id;
　　}else{
　　　　$brand_id .= $v->brand_id;
　　}
}

$brand_id = ltrim($brand_id,',');

$condition .= " or brand_id in($brand_id) ";
}