精妙的"SQL"語句:
◆復制表(只復制結構,源表名：a 新表名：b)
SQL: select * into b from a where 1<>1
◆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;
◆顯示文章、提交人和最後回復時間
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開始時間,getdate())>5
◆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') ¦¦ '/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。
