按照小时显示更新数量怎么实现

用sql调用
12小时：<?=$empire->gettotal("select count(*) as total from phome_ecms_表 where newstime>UNIX_TIMESTAMP()-24*3600")?>
6小时：<?=$empire->gettotal("select count(*) as total from phome_ecms_表 where newstime>UNIX_TIMESTAMP()-6*3600")?>