substr(string,1,8)
1.
//将一个表中符合条件的记录批量更新到另外一张表。(假设表名为:toffice,tofficetemp)
update toffice a
set a.office_code = (select b.office_code from tofficetemp b where a.jgdm = b.jgdm)
where a.jgdm in (select jgdm from tofficetemp)
update tofficenexas set isuse = '0' where rowid in
(select rowid from tofficenexas a where
rowid !=(select max(rowid) from tofficenexas b where a.office_id = b.office_id and
a.father_office_id = b.father_office_id and a.big_kind_id =b.big_kind_id))
2
//查询某个时间段的值
select * from tdespatch t
where t.out_time between to_date('2005-10-18 15:47:42','yyyy-mm-dd hh24:mi:ss')
and to_date('2005-10-20 10:47:42','yyyy-mm-dd hh24:mi:ss')
3。
//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
4。
//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;
5。
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
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
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
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 )
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
WHERE A.NUM = B.NUM
说明:--
SQL:
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
说明:
从数据库中去一年的各单位电话费统计(电话费定额贺电化肥清单两个表来源)
SQL:
SELECT a.userper, a.tel, a.standfee, TO_CHAR(a.telfeedate, 'yyyy') AS telyear,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '01', a.factration)) AS JAN,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '02', a.factration)) AS FRI,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '03', a.factration)) AS MAR,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '04', a.factration)) AS APR,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '05', a.factration)) AS MAY,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '06', a.factration)) AS JUE,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '07', a.factration)) AS JUL,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '08', a.factration)) AS AGU,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '09', a.factration)) AS SEP,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '10', a.factration)) AS OCT,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '11', a.factration)) AS NOV,
SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '12', a.factration)) AS DEC
FROM (SELECT a.userper, a.tel, a.standfee, b.telfeedate, b.factration
FROM TELFEESTAND a, TELFEE b
WHERE a.tel = b.telfax) a
GROUP BY a.userper, a.tel, a.standfee, TO_CHAR(a.telfeedate, 'yyyy')
说明:四表联查问题:
SQL: select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....
说明:得到表中最小的未使用的ID号
SQL:
SELECT (CASE WHEN EXISTS(SELECT * FROM Handle b WHERE b.HandleID = 1) THEN MIN(HandleID) + 1 ELSE 1 END) as HandleID
FROM Handle
WHERE NOT HandleID IN (SELECT a.HandleID - 1 FROM Handle a)
6 根据父表 只取子表最新的一条记录{
SQL> select * from testa ;
F1
----------
1
2
3
SQL> select * from testb ;
F1 F2
---------- -------------------
1 2006-04-10 14:56:41
1 2006-04-10 14:56:53
1 2006-04-10 14:57:00
2 2006-04-10 14:57:08
3 2006-04-10 14:57:19
3 2006-04-10 14:57:25
6 rows selected.
SQL> select testa.f1,v1.f1,v1.f2 from testa ,(select f1,f2,row_number() over (partition by f1 order
by f2 desc) rn from testb) v1 where testa.f1 = v1.f1 and v1.rn = 1 ;
F1 F1 F2
---------- ---------- -------------------
1 1 2006-04-10 14:57:00
2 2 2006-04-10 14:57:08
3 3 2006-04-10 14:57:25
------------------------------------------
7 查询语句的优化
select t.* from acc$ t
where
not exists (在此不使用not in 是为了性能上的考虑)
(select 'a' from crm$ a
where
a.客户名=t.用户名称
--a.客户号=t.用户编号
)
posted on 2005-10-30 09:42
surffish 阅读(276)
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