string deviceCode=dt.Rows[i]["code"].ToString(); string sql_logtime = @"select stuff(( select ','+CONVERT(Nvarchar,l2.logtime, 20) from logs_signIn l2 where CONVERT(Nvarchar,l2.logtime, 23)='" + DateTime.Now.ToString("yyyy-MM-dd") + @"' order by l2.logtime desc FOR XML PATH('')) ,1,1,'') logtimes "; object obj = DbHelperSQL.GetSingle(sql_logtime);