SQL语句介绍

bxue · 发表于 2010-8-15 18:20:07

精妙SQL语句介绍
1. 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

2. 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

3. 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

4. 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

5. 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

6. 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)

7. 说明：——
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;
　
8. 说明：——
select *
from studentinfo
where not exists(select * from student where studentinfo.id=student.id)
and 系名称=''"&strdepartmentname&"''
and 专业名称=''"&strprofessionname&"''
order by 性别, 生源地, 高考总成绩