說明：復(fù)制表(只復(fù)制結(jié)構(gòu),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(shù)據(jù),源表名：a 目標(biāo)表名：b)
sql: insert into b(a, b, c) select d,e,f from b;

說明：顯示文章、提交人和最后回復(fù)時(shí)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：外連接查詢(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：日程安排提前五分鐘提醒
sql: select * from 日程安排 where datediff('minute',f開始時(shí)間,getdate())>5

說明：兩張關(guān)聯(lián)表，刪除主表中已經(jīng)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') ¦¦ '/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(yè)名稱='"&strprofessionname&"' order by 性別,生源地,高考總成績

說明：
從數(shù)據(jù)庫中去一年的各單位電話費(fèi)統(tǒng)計(jì)(電話費(fèi)定額賀電化肥清單兩個(gè)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(lián)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：得到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)