SQL DISTINCT去掉重复的数据统计方法
备注：SELECT `log_id`,count(*) as count FROM `dp_im_chat` GROUP BY `log_id` HAVING count>1
public function clear_trush_data()
{
$data=db('im_chat')->field('log_id,count(*) as count')
->group('log_id')->having('count>1')->select();
dump($data);
foreach ($data as $k=>$v){
$check=db('im_chat')->where('log_id',$v['log_id'])->value('id');
$clear=db('im_chat')->where('log_id',$v['log_id'])->where('id','neq',$check)->delete();
dump(db('')->getLastSql());
}
}
