$end=date("Y-m-d H:i:s");
$enddays=" and startday<='$end' and endday > '$end' and ordercnt!=sg_mnt";

// 프리미엄
select * from nara_sangpum where cod='O' and apremium != '' $enddays order by no desc limit 6

// 1000원샾
select * from nara_sangpum where cod='O' and thousand != '' and (aci_code like '01%' or aci_code like '03%') $enddays order by RAND() limit 4
select * from nara_sangpum where cod='O' and thousand != '' and (aci_code like '05%' or aci_code like '06%' or aci_code like '07%' or aci_code like '08%') $enddays order by RAND() limit 4

// 옥션포커스
select * from nara_sangpum where cod='O' and focus != '' $enddays order by RAND() limit 24

// 특이물품코너
select * from nara_sangpum where cod='O' and special != '' and (aci_code like '01%' or aci_code like '03%') $enddays order by RAND() desc limit 6
select * from nara_sangpum where cod='O' and special != '' and (aci_code like '02%' or aci_code like '04%') $enddays order by RAND() desc limit 6
select * from nara_sangpum where cod='O' and special != '' and (aci_code like '05%' or aci_code like '06%' or aci_code like '07%' or aci_code like '08%') $enddays order by RAND() desc limit 6

// 신규등록5
select * from nara_sangpum where cod='O' and aci_code like '01%' $enddays order by no desc limit 5
select * from nara_sangpum where cod='O' and aci_code like '02%' $enddays order by no desc limit 5
select * from nara_sangpum where cod='O' and aci_code like '04%' $enddays order by no desc limit 5

// 마감임박5
select * from nara_sangpum where cod='O' and aci_code like '01%' $enddays order by endday asc limit 5
select * from nara_sangpum where cod='O' and aci_code like '02%' $enddays order by endday asc limit 5
select * from nara_sangpum where cod='O' and aci_code like '03%' $enddays order by endday asc limit 5
select * from nara_sangpum where cod='O' and aci_code like '04%' $enddays order by endday asc limit 5
select * from nara_sangpum where cod='O' and (aci_code like '05%' or aci_code like '06%' or aci_code like '07%' or aci_code like '08%') $enddays order by endday asc limit 5

테이블 구조는 아래와 같습니다.
특별히 테이블 필드구조를 바꿈으로써도 sql 속도를 높일 수 있는 방법도 있는지요?

CREATE TABLE `nara_sangpum` (
  `no` int(10) unsigned NOT NULL auto_increment,
  `main_no` int(10) default '0',
  `code` varchar(10) NOT NULL default '',
  `aci_code` varchar(30) default NULL,
  `aci_cname` varchar(200) NOT NULL default '',
  `sgname` varchar(150) NOT NULL default '',
  `card` enum('y','n') default NULL,
  `cardprice` enum('y','n') default NULL,
  `receipt` varchar(70) default NULL,
  `sobija_mnt` int(30) default NULL,
  `sm_comment` mediumtext,
  `content` mediumtext,
  `comment_type` char(2) default NULL,
  `viewcnt` int(10) default '0',
  `max_ordercnt` int(10) default '0',
  `ordercnt` int(10) default '0',
  `regdate` int(10) NOT NULL default '0',
  `jukrip_mnt` int(10) default '0',
  `halin_mnt` int(10) default NULL,
  `common_info` mediumtext,
  `lank` int(1) default '0',
  `sg_code` varchar(50) default NULL,
  `sg_mnt` int(10) default '0',
  `shopname` varchar(50) default NULL,
  `sgname1` varchar(150) default NULL,
  `lanking` varchar(30) default NULL,
  `auction` enum('C','N','G') default NULL,
  `startday` varchar(50) default NULL,
  `endday` varchar(50) default NULL,
  `startprice` varchar(50) default NULL,
  `plusprice` varchar(50) default NULL,
  `baisong` varchar(30) default NULL,
  `unsong` varchar(100) default NULL,
  `f_file1` varchar(255) default NULL,
  `f_file2` varchar(255) default NULL,
  `f_file3` varchar(255) default NULL,
  `f_file4` varchar(255) default NULL,
  `f_file5` varchar(255) default NULL,
  `premium` varchar(50) default NULL,
  `apremium` varchar(50) default NULL,
  `Special` varchar(50) default NULL,
  `thousand` varchar(50) default NULL,
  `focus` varchar(50) default NULL,
  `bold` varchar(50) default NULL,
  `see` varchar(50) default NULL,
  `endproduct` varchar(50) default NULL,
  `auto` varchar(50) default NULL,
  `totalfee` varchar(50) default NULL,
  `userid` varchar(50) default NULL,
  `auction_date` varchar(10) default NULL,
  `pre` int(1) default '2',
  `nowprice` int(11) default NULL,
  `tender` int(11) default '0',
  `cod` enum('O','X') default 'O',
  `cod_text` mediumtext,
  `cod_email` varchar(100) default NULL,
  `product_see` int(30) default '0',
  `endchance` int(1) default '0',
  PRIMARY KEY  (`no`)
) TYPE=MyISAM