说明：复制表(只复制结构,源表名：a 新表名：b)
select * into b from a where 1 <>1
说明：拷贝表(拷贝数据,源表名：a 目标表名：b)
insert into b(a, b, c) select d,e,f from b;
说明：显示文章、提交人和最后回复时间
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
说明：外连接查询(表名1：a 表名2：b)
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
说明：日程安排提前五分钟提醒
select * from 日程安排 where datediff('minute',f开始时间,getdate())>5
说明：两张关联表，删除主表中已经在副表中没有的信息
delete from info where not exists ( select * from infobz where info.infid=infobz.infid )
说明：--
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
