精妙地sql語(yǔ)句:
◆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
◆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;
◆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
◆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
◆兩張關(guān)聯(lián)表，刪除主表中已經(jīng)在副表中沒有地信息
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(jī)