left outer

select a.uid,a.book_name from ins_book_shop a left outer join lecture b on (a.uid = b.book_uid) where b.lecture_name like '%semi%';

 
 
 
alter table ins_news_enterprise_etc add index user_idx(town_uid,town_table);
alter table ins_news_section add index user_idx2(section,section_onoff,cate_level)
alter table ins_news add index user_idx4(uid,wdate);
alter table ins_news_section drop index user_idx2;

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order by 를 두개 이상 쓰지 말자
 
order by wdate DESC,uid DESC  이런것