1. 说明：复制表(只复制结构，源表名：a，新表名：b)
SQL: select * into b from a where 1<>1;
2. 说明：拷贝表(拷贝数据，源表名：a，目标表名：b)
SQL: insert into b(a, b, c) select d, e, f from b;
3. 说明：显示文章、提交人和最后回复时间
SQL: select a.title, a.username, b.adddate
from table a,(
select max(adddate) adddate
from table where table.title=a.title) b
4. 说明：外连接查询(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;
5. 说明：日程安排提前五分钟提醒
SQL: select *
from 日程安排
where datediff(’’minute’’, f开始时间, getdate())>5
6. 说明：两张关联表，删除主表中已经在副表中没有的信息
SQL: delete from info
where not exists(
select *
from infobz
where info.infid=infobz.infid );
7. 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’’) - 1, ’’YYYY/MM’’) ) Y,
WHERE X.NUM = Y.NUM （+）AND X.INBOUND_QTY
+ NVL(Y.STOCK_ONHAND,0) <> X.STOCK_ONHAND ) B
