精妙SQL語句介紹

　　說明：複製表(只複製結構,源表名：a 新表名：b)　　 

　　sql: select * into b from a where 1<>1 

　　說明：拷貝表(拷貝數據,源表名：a 目標表名：b)　　 

　　sql: insert into b(a, b, c) select d,e,f from b; 

　　說明：顯示文章、提交人和最後回覆時間　　 

　　sql: select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 

　　說明：外鏈接查詢(表名1：a 表名2：b)　　 

　　sql: select a.a, a.b, a.c, b.c, b.d, b.f from a left out join b on a.a = b.c 

　　說明：日程安排提早五分鐘提醒　　 

　　sql: select * from 日程安排 where datediff(''minute'',f開始時間,getdate())>5　　 

　　說明：兩張關聯表，刪除主表中已經在副表中沒有的信息 

　　sql: 　　 

　　delete from info where not exists ( select * from infobz where info.infid=infobz.infid 

　　說明：-- 

　　sql: 　　 

　　select a.num, a.name, b.upd_date, b.prev_upd_date 

　　 from table1, 

　　 (select x.num, x.upd_date, y.upd_date prev_upd_date 

　　 from (select num, upd_date, inbound_qty, stock_onhand 

　　 from table2 

　　 where to_char(upd_date,''yyyy/mm'') = to_char(sysdate, ''yyyy/mm'')) x, 

　　 (select num, upd_date, stock_onhand 

　　 from table2 

　　 where to_char(upd_date,''yyyy/mm'') = 

　　 to_char(to_date(to_char(sysdate, ''yyyy/mm'') &brvbar;&brvbar; ''/01'',''yyyy/mm/dd'') - 1, ''yyyy/mm'') y, 

　　 where x.num = y.num （+） 

　　 and x.inbound_qty + nvl(y.stock_onhand,0) <> x.stock_onhand b 

　　where a.num = b.num 

　　說明：-- 

　　sql: 　　 

　 　select * from studentinfo where not exists(select * from student where studentinfo.id=student.id) and 系名稱=''"&strdepartmentname&"'' and 專業名稱=''"&strprofessionname&"'' order by 性別,生源地,高考總成績 

　　說明： 

　　從數據庫中去一年的各單位電話費統計(電話費定額賀電化肥清單兩個表來源） 

　　sql: 　 

　　select a.userper, a.tel, a.standfee, to_char(a.telfeedate, ''yyyy'') as telyear, 

　　 sum(decode(to_char(a.telfeedate, '' mm  ''), ''01'', a.factration)) as jan, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''02'', a.factration)) as fri, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''03'', a.factration)) as mar, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''04'', a.factration)) as apr, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''05'', a.factration)) as may, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''06'', a.factration)) as jue, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''07'', a.factration)) as jul, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''08'', a.factration)) as agu, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''09'', a.factration)) as sep, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''10'', a.factration)) as oct, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''11'', a.factration)) as nov, 

　　 sum(decode(to_char(a.telfeedate, ''mm''), ''12'', a.factration)) as dec 

　　from (select a.userper, a.tel, a.standfee, b.telfeedate, b.factration 

　　 from telfeestand a, telfee b 

　　 where a.tel = b.telfax) a 

　　group by a.userper, a.tel, a.standfee, to_char(a.telfeedate, ''yyyy'') 

　　說明：四表聯查問題：　　 

　　sql: select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 

　　說明：獲得表中最小的未使用的id號 

　　sql:　 

　　select (case when exists(select * from handle b where b.handleid = 1) then min(handleid) + 1 else 1 end) as handleid 

　　 from handle 

　　 where not handleid in (select a.handleid - 1 from handle a)