]]>
- 阶段1Q服务器(g)查是否允怽q接?/li>
- 阶段2Q假定你能连接，服务器检查你发出的每个请求。看你是否有_的权限实施它。例如，如果你从数据库表中选择(select)行或从数据库删除表，服务器确定你对表?span>SELECT权限或对数据库有DROP权限?/li>
1.权限查看
mysql> show grants for 'root'@'localhost' ;
+---------------------------------------------------------------------+
| Grants for root@localhost |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
+---------------------------------------------------------------------+
1 row in set (0.06 sec)
+---------------------------------------------------------------------+
| Grants for root@localhost |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
+---------------------------------------------------------------------+
1 row in set (0.06 sec)
2.权限讄
5.8.2. 向MySQL增加新用戯̎?/a>
mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost'
-> I(yng)DENTIFIED BY 'some_pass' WITH GRANT OPTION;
mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%'
-> I(yng)DENTIFIED BY 'some_pass' WITH GRANT OPTION;
其中两个账户有相同的用户?span>monty和密?span>some_pass。两个̎户均U用戯̎Ph完全的权限可以做M事情。一个̎?span> ('monty'@'localhost')只用于从本机q接时。另一个̎?span>('monty'@'%')可用于从其它Lq接?/font>
mysql> GRANT RELOAD,PROCESS ON *.* TO 'admin'@'localhost';
该̎户只用于从本接。授予了(jin)RELOAD?span>PROCESS理权限。这些权限允?span>admin用户执行mysqladmin reload?strong>mysqladmin refresh?strong>mysqladmin flush-xxx命o(h)Q以?strong>mysqladmin processlist。未授予讉K数据库的权限。你可以通过GRANT语句d此类权限?/font>
mysql> GRANT USAGE ON *.* TO 'dummy'@'localhost';
一个̎h用户?span>dummyQ没有密码。该账户只用于从本机q接。未授予权限。通过GRANT语句中的USAGE权限Q你可以创徏账户而不授予M权限。它可以所有全局权限设ؓ(f)'N'。假定你在以后具体权限授予该账户?/font>
-> I(yng)DENTIFIED BY 'some_pass' WITH GRANT OPTION;
mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%'
-> I(yng)DENTIFIED BY 'some_pass' WITH GRANT OPTION;
其中两个账户有相同的用户?span>monty和密?span>some_pass。两个̎户均U用戯̎Ph完全的权限可以做M事情。一个̎?span> ('monty'@'localhost')只用于从本机q接时。另一个̎?span>('monty'@'%')可用于从其它Lq接?/font>
mysql> GRANT RELOAD,PROCESS ON *.* TO 'admin'@'localhost';
该̎户只用于从本接。授予了(jin)RELOAD?span>PROCESS理权限。这些权限允?span>admin用户执行mysqladmin reload?strong>mysqladmin refresh?strong>mysqladmin flush-xxx命o(h)Q以?strong>mysqladmin processlist。未授予讉K数据库的权限。你可以通过GRANT语句d此类权限?/font>
mysql> GRANT USAGE ON *.* TO 'dummy'@'localhost';
一个̎h用户?span>dummyQ没有密码。该账户只用于从本机q接。未授予权限。通过GRANT语句中的USAGE权限Q你可以创徏账户而不授予M权限。它可以所有全局权限设ؓ(f)'N'。假定你在以后具体权限授予该账户?/font>
下面的例子创?span>3个̎P允许它们讉K专用数据库。每个̎L(fng)用户名ؓ(f)customQ密码ؓ(f)obscure?br />
mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP
-> ON bankaccount.*
-> TO 'custom'@'localhost'
-> I(yng)DENTIFIED BY 'obscure';
mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP
-> ON expenses.*
-> TO 'custom'@'whitehouse.gov'
-> I(yng)DENTIFIED BY 'obscure';
mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP
-> ON customer.*
-> TO 'custom'@'server.domain'
-> I(yng)DENTIFIED BY 'obscure';
q?个̎户可以用于：(x)
· W?个̎户可以访问bankaccount数据库，但只能从本机讉K?br />
· W?个̎户可以访问expenses数据库，但只能从Lwhitehouse.gov讉K?br />
· W?个̎户可以访问customer数据库，但只能从Lserver.domain讉K?br />
要想不用GRANT讄custom账户Q用INSERT语句直接修改 授权表：(x)
5.8.3. 从MySQL删除用户账户
DROP USER user;
]]>
create table test.level (name varchar(20));
?insert 些数?;
/*初始?/span>*/
drop procedure if exists useCursor //
/*建立 存储q程 create */
CREATE PROCEDURE useCursor()
BEGIN
/*局部变量的定义 declare*/
declare tmpName varchar(20) default '' ;
declare allName varchar(255) default '' ;
declare cur1 CURSOR FOR SELECT name FROM test.level ;
/* mysql 不知道ؓ(f)什么用异常加入判断 Q?br /> * 此请参考官Ҏ(gu)?20.2.11. 光标 光标
* q把 游标 异常后 捕捉?br /> * q设| @环用 变量 tmpname 为 null 跛_循环?br /> */
declare CONTINUE HANDLER FOR SQLSTATE '02000' SET tmpname = null;
/*开游标*/
OPEN cur1;
/*游标向下C?/span>*/
FETCH cur1 INTO tmpName;
/* 循环体 这很明显 把游标查询出的 name 都加起ƈ用? 号隔开 */
WHILE ( tmpname is not null) DO
set tmpName = CONCAT(tmpName ,";") ;
set allName = CONCAT(allName ,tmpName) ;
/*游标向下C?/span>*/
FETCH cur1 INTO tmpName;
END WHILE;
CLOSE cur1;
select allName ;
END;//
call useCursor()//
drop procedure if exists useCursor //
/*建立 存储q程 create */
CREATE PROCEDURE useCursor()
BEGIN
/*局部变量的定义 declare*/
declare tmpName varchar(20) default '' ;
declare allName varchar(255) default '' ;
declare cur1 CURSOR FOR SELECT name FROM test.level ;
/* mysql 不知道ؓ(f)什么用异常加入判断 Q?br /> * 此请参考官Ҏ(gu)?20.2.11. 光标 光标
* q把 游标 异常后 捕捉?br /> * q设| @环用 变量 tmpname 为 null 跛_循环?br /> */
declare CONTINUE HANDLER FOR SQLSTATE '02000' SET tmpname = null;
/*开游标*/
OPEN cur1;
/*游标向下C?/span>*/
FETCH cur1 INTO tmpName;
/* 循环体 这很明显 把游标查询出的 name 都加起ƈ用? 号隔开 */
WHILE ( tmpname is not null) DO
set tmpName = CONCAT(tmpName ,";") ;
set allName = CONCAT(allName ,tmpName) ;
/*游标向下C?/span>*/
FETCH cur1 INTO tmpName;
END WHILE;
CLOSE cur1;
select allName ;
END;//
call useCursor()//
q行l果Q?br />
mysql> call useCursor()//
+--------------------------------------+
| allName |
+--------------------------------------+
| f1;c3;c6;c5;c2;c4;c1;f1;f3;f4;f2;f5; |
+--------------------------------------+
1 row in set (0.00 sec)
+--------------------------------------+
| allName |
+--------------------------------------+
| f1;c3;c6;c5;c2;c4;c1;f1;f3;f4;f2;f5; |
+--------------------------------------+
1 row in set (0.00 sec)
]]>
delimiter //
create trigger a_bi
before insert on a
for each row Begin
if new.s2=0 then
if(new.s3=1) then
insert into b(s2) values(new.s1);
elseif(new.s3=2)then
insert into c(s2) values(new.s1);
end if;
end if;
end;//
delimiter ;
create trigger a_bi
before insert on a
for each row Begin
if new.s2=0 then
if(new.s3=1) then
insert into b(s2) values(new.s1);
elseif(new.s3=2)then
insert into c(s2) values(new.s1);
end if;
end if;
end;//
delimiter ;
]]>
--================================================
1.增加主键
alter table TABLE_NAME add constraint KEY_NAME primary key (TABLE_COLUMN);
指定表空?br /> alter table TABLE_NAME add constraint KEY_NAME primary key (TABLE_COLUMN) using index tablespace TABLE_SPACE_NAME;
2.增加外键
alter table TABLE_NAME add constraint FK_NAME foreign key (TABLE_COLUMN) references KEY_TABLE_NAME;
3.使主键或外键失效、生?br /> alter table TABLE_NAME disable(enable) constraint KEY_NAME;
4、查看各U约?br /> select constraint_name,table_name,constraint_type,status from user_constraints;
select constraint_name, constraint_type,search_condition, r_constraint_name from user_constraints where table_name = upper('&table_name')
select c.constraint_name,c.constraint_type,cc.column_name
from user_constraints c,user_cons_columns cc
where c.owner = upper('&table_owner') and c.table_name = upper('&table_name')
and c.owner = cc.owner and c.constraint_name = cc.constraint_name
order by cc.position;
5、删除主键或外键
alter table TABLE_NAME drop constraint KEY_NAME;
6、徏外键
单字D|Qcreate table 表名 (col1 char(8),
cno char(4) REFERENCE course);
多个字段?在最后加?Foreign Key (字段? REFERENCE 表名(字段)
q带删除选项 (on delete cascade
当指定时Q如果父表中的记录被删除Q则依赖于父表的记录也被删除
REFERENCE 表名Q）(j) on delete cascade;
7、删除带U束的表
Drop table 表名 cascade constraints;
8Q烦(ch)引管?br /> <1>.creating function-based indexes
sql> create index summit.item_quantity on summit.item(quantity-quantity_shipped);
<2>.create a B-tree index
sql> create [unique] index index_name on table_name(column,.. asc/desc) tablespace
sql> tablespace_name [pctfree integer] [initrans integer] [maxtrans integer]
sql> [logging | nologging] [nosort] storage(initial 200k next 200k pctincrease 0
sql> maxextents 50);
<3>.pctfree(index)=(maximum number of rows-initial number of rows)*100/maximum number of rows
<4>.creating reverse key indexes
sql> create unique index xay_id on xay(a) reverse pctfree 30 storage(initial 200k
sql> next 200k pctincrease 0 maxextents 50) tablespace indx;
<5>.create bitmap index
sql> create bitmap index xay_id on xay(a) pctfree 30 storage( initial 200k next 200k
sql> pctincrease 0 maxextents 50) tablespace indx;
<6>.change storage parameter of index
sql> alter index xay_id storage (next 400k maxextents 100);
7.allocating index space
sql> alter index xay_id allocate extent(size 200k datafile 'c:/oracle/index.dbf');
<8>.alter index xay_id deallocate unused;
<9>、查看烦(ch)?br /> SQL>select index_name,index_type,table_name from user_indexes order by table_name;
<10>、查看烦(ch)引被索引的字D?br /> SQL>select * from user_ind_columns where index_name=upper('&index_name');
11、创建序?br /> select * from user_sequences;
create sequence SEQ_NAME start with 1000
maxvalue 1000 increment by 1;
alter sequence SEQ_NAME minvalue 50 maxvalue 100;
12、删除重复行
update a set aa=null where aa is not null;
delete from a where rowid!=
(select max(rowid) from a b where a.aa=b.aa);
13、删除同其他表相同的?br /> delete from a where exits
(select 'X' from b where b.no=a.no);
?br /> delete from a where no in (select no from b);
14、查询从多少行到多少行的记录(可以用在web开发中的分|C?
select * from ( select rownum row_id,b.* from (select a.* from sys_oper a) b )
where row_id between 15 and 20
15、对公共授予讉K?br /> grant select on 表名 to public;
create public synonym 同义词名 for 表名;
16、填加注?br /> comment on table 表名 is '注释';
comment on column 表名.列名 is '注释';
17、分布式数据?创徏数据库链?br /> create [public] database link LINKNAME
[connect to USERNAME identified by PASSWORD]
[using 'CONNECT_STRING']
可以在服务器端，也可以在客户端徏立，但必L意，两台服务器之?br /> 数据库必d以互访，必须各有各自的别名数据库
18、查看数据库链\
select * from all_db_links;
select * from user_db_links;
查询 select * from TABLENAME@DBLNKNAME;
创徏q程数据库同义词
create synonym for TABLENAME@DBLNKNAME;
操纵q程数据库记?br /> insert into TABLENAME@DBLNKNAME (a,b) values (va,vb);
update TABLENAME@DBLNKNAME set a='this';
delete from TABLENAME@DBLNKNAME;
怎样执行q程的内嵌过E?br /> begin
otherdbpro@to_html(参数);
end;
19、数据库链\用户密码有特D字W的时候，可以用双引号把密码引h
create public database link dblink1 connect to db1 identified by "123*456" using 'db11'
20.oracle8中扩充了(jin)group by rollup和cube的操作。有时候省?jin)你好多功夫的?br /> <1>下面的语句可以进行总计
select region_code,count(*) from aicbs.acc_woff_notify
group by rollup(region_code);
<2> 对第1个字D小计，最后合?br /> select region_code,write_status,count(*) from aicbs.acc_woff_notify
group by rollup(region_code,write_status);
----------------------
570 0 3
570 1 2
570 5 --此处计?70的记?br /> 571 0 10
571 1 2
571 12 --此处计?71的记?br /> .....
100 --此处有总计
<3> 复合rollup表达?只做总计
select region_code,write_status,count(*) from aicbs.acc_woff_notify
group by rollup(region_code,write_status);
<4> 对第1个字D小计，再对W?个字D小计，最后合?br /> select region_code,write_status,count(*) from aicbs.acc_woff_notify
group by cube(region_code,write_status);
----------------------
100 --此处有总计
0 60 --对write_statusQ?的小?br /> 1 39 --对write_statusQ?的小?br /> 3 1 --对write_statusQ?的小?br /> 570 5 --此处计?70的记?br /> 570 0 3
570 1 2
571 12 --此处计?71的记?br /> 571 0 10
571 1 2
....
<3> 复合cube表达?只做总计
select region_code,write_status,count(*) from aicbs.acc_woff_notify
group by cube(region_code,write_status);
<4>下面的语句可以按照rollup不同的字D进行小?br /> select region_code,write_status,count(*) from aicbs.acc_woff_notify
group by region_code,rollup(write_status);
21.查询view的创?br /> sql>set long 1000
sql>select * from user_views where view_name='MY_VIEW_NAME';
or
sql>select * from all_views where view_name='MY_VIEW_NAME';
22、去除数据库中特D字W?br /> <1>.字符串字D中含有"'",如果用来l合sql语句Q会(x)造成语句不准?br /> 比如Qreplace(f1,'''','')
<2>.字符串字D中含有"\t \n",如果用来在c或者cQ＋E序中输出到文gQ格式无法保证?br /> 比如Qreplace(f2,'\t','')
<3>.清除换行和回?br /> 比如: replace(f2,chr(13)||chr(10),'')
23、如何在字符串里加回车或者tab?
在sqlplus中执?br /> sql>select 'UserId=1233111'||chr(10)||'AccId=13431'||chr(9)||'AccId2=11111' from dual;
24、树(wi)形查?br /> create table zj(
bm number(8),
bmmc varchar2(20),
sjbm number(8)
)
insert into zj values(1,'aaa',0)
insert into zj values(11,'aaa1',1)
insert into zj values(12,'aaa2',1)
insert into zj values(111,'aaa11',11)
insert into zj values(112,'aaa12',11)
insert into zj values(113,'aaa13',11)
insert into zj values(121,'aaa21',12)
insert into zj values(122,'aaa22',12)
insert into zj values(123,'aaa23',12)
--
select bm,bmmc,sjbm,level
from zj
start with sjbm=0
connect by prior bm = sjbm
或?br /> select bm,bmmc,sjbm,level
from zj
start with sjbm=0
connect by sjbm = prior bm
25、快?br /> create snapshot SNAPSHOT_NAME
[storage (storage parameter)]
[refresh [fast\complete\force]
[start with START_DATE next NEXT_DATE]
as QUERY;
create snapshot snapshot_to_study as select * from TABLE_NAME@to_study;
创徏角色
create role aa identified by aaa;
授权 grant create snapshot,alter snapshot to aaa;
grant aaa to emp;
create snapshot SNAPSHOT_TO_HTML refresh complete start with sysdate next
sysdate+5/(24*60*60) as select * from a@to_html;
删除 drop snapshot snap_to_html
手工h快照,(调用DBMS_SNAPSHOT包中的refreshq程)DBMS_SNAPSHOT.refresh(snapshot_name,refresh_type);
begin
DBMS_SNAPSHOT.REFRESH('snap_to_html','c');
end;
Ҏ(gu)有快照进行刷?br /> begin
DBMS_SNAPSHOT.REFRESH_ALL;
end;
怎样执行q程的内嵌过E?br /> begin
otherdbpro@to_html(参数);
end;
26、用L(fng)?br /> create a user: database authentication
sql> create user juncky identified by oracle default tablespace users
sql> temporary tablespace temp quota 10m on data password expire
sql> [account lock|unlock] [profile profilename|default];
<1>.查看当前用户的缺省表I间
SQL>select username,default_tablespace from user_users;
<2>生成用户时指定缺省表I间
create user 用户?identified by 口o(h) default tablespace 表空间名;
<3>重新指定用户的缺省表I间
alter user 用户?default tablespace 表空间名
<4>查看当前用户的角?br /> SQL>select * from user_role_privs;
<5>查看当前用户的系l权限和表权限
SQL>select * from user_sys_privs;
SQL>select * from user_tab_privs;
<6>查看用户下所有的?br /> SQL>select * from user_tables;
<7> alter user语句的quota子句限制用户的磁盘空?br /> ?alter user jf quota 10M on system;
27、查看放在ORACLE的内存区里的?
SQL>select table_name,cache from user_tables where instr(cache,'Y')>0;
28、约束条?br /> create table employee
(empno number(10) primary key,
name varchar2(40) not null,
deptno number(2) default 10,
salary number(7,2) check salary<10000,
birth_date date,
soc_see_num char(9) unique,
foreign key(deptno) references dept.deptno)
tablespace users;
关键?primary key)必须是非I?表中记录的唯一?br /> not null 非空U束
default ~省值约?br /> check (g)查约?使列的值符合一定的标准范围
unqiue 唯一性约?br /> foreign key 外部键约?br /> 29、查看创囄select语句
SQL>set view_name,text_length from user_views;
SQL>set long 2000; 说明Q可以根据视囄text_lengthD定set long 的大?br /> SQL>select text from user_views where view_name=upper('&view_name');
30、查看同义词的名U?br /> SQL>select * from user_synonyms;
31、用Sql语句实现查找一列中WN大?
select * from
(select t.*,dense_rank() over (order by sal) rank from employee)
where rank = N;
32 虚拟自段
<1>. CURRVAL ?nextval
创徏序列
CREATE SEQUENCE EMPSEQ ... ;
SELECT empseq.currval FROM DUAL ;
自动插入序列的数?br /> INSERT INTO emp
VALUES (empseq.nextval, 'LEWIS', 'CLERK',
7902, SYSDATE, 1200, NULL, 20) ;
<2>. ROWNUM
按设定排序的行的序号
SELECT * FROM emp WHERE ROWNUM < 10 ;
<3>. ROWID
q回行的物理地址
SELECT ROWID, ename FROM emp WHERE deptno = 20 ;
33、对CLOB字段q行全文(g)?br /> SELECT * FROM A WHERE dbms_lob.instr(a.a,'K',1,1)>0;
34. Ҏ(gu)字符的插入，比如"&"
insert into a values (translate ('at{&}t','at{}','at'));
35.表管?br /> <1>.create a table
sql> create table table_name (column datatype,column datatype]....)
sql> tablespace tablespace_name [pctfree integer] [pctused integer]
sql> [initrans integer] [maxtrans integer]
sql> storage(initial 200k next 200k pctincrease 0 maxextents 50)
sql> [logging|nologging] [cache|nocache]
<2>.copy an existing table
sql> create table table_name [logging|nologging] as subquery
<3> create table ... as 方式的时候，指定表参?br /> create table a
storage(
initial 1M /*W一ơ创建时分配I间*/
next 1M /*W一ơ分配的存储I间用完时在分配*/
)
as select * from b;
<4>.创徏临时?br /> sql> create global temporary table xay_temp as select * from xay;
on commit preserve rows/on commit delete rows
在Oracle中，可以创徏以下两种临时?
a ?x)话?gu)的(f)时表:
create global temporary table () on commit preserve rows;
?x)话指定Q当中断?x)话时ORACLE截断表
b 事务Ҏ(gu)的(f)时表:
create global temporary table () on commit delete rows;
事务指定,每次提交后ORACLE截断表Q删除全部行Q?
c 说明
临时表只在当前连接内有效
临时表不建立索引,所以如果数据量比较大或q行多次查询?不推荐?
数据处理比较复杂的时候时表快,反之视图快点
在仅仅查询数据的时候徏议用游标: open cursor for 'sql clause';
<5>
pctfree = (average row size - initial row size) *100 /average row size
pctused = 100-pctfree- (average row size*100/available data space)
<6>.change storage and block utilization parameter
sql> alter table table_name pctfree=30 pctused=50 storage(next 500k
sql> minextents 2 maxextents 100);
<7>.manually allocating extents
sql> alter table table_name allocate extent(size 500k datafile 'c:/oracle/data.dbf');
<8>.move tablespace
sql> alter table employee move tablespace users;
<9>.deallocate of unused space
sql> alter table table_name deallocate unused [keep integer]
<10>.drop a column
sql> alter table table_name drop column comments cascade constraints checkpoint 1000;
alter table table_name drop columns continue;
<11>.mark a column as unused
sql> alter table table_name set unused column comments cascade constraints;
alter table table_name drop unused columns checkpoint 1000;
alter table orders drop columns continue checkpoint 1000
data_dictionary : dba_unused_col_tabs
37. 中文是如何排序的Q?
Oracle9i之前Q中文是按照二进制编码进行排序的?
在oracle9i中新增了(jin)按照拼音、部首、笔L序功能。设|NLS_SORT?
SCHINESE_RADICAL_M 按照部首Q第一序Q、笔划（W二序Q排?
SCHINESE_STROKE_M 按照W划Q第一序Q、部首（W二序Q排?
SCHINESE_PINYIN_M 按照拼音排序
38. 数据表中的字D|大数:
表或视图中的最大列Cؓ(f) 1000
39. oracle中的裸设?
裸设备就是绕q文件系l直接访问的储存I间
40. 在Oracle服务器上通过SQLPLUS查看本机IP地址 ?
select sys_context('userenv','ip_address') from dual;
如果是登陆本机数据库Q只能返?27.0.0.1
41. 在ORACLE中取毫秒?
9i之前不支?9i开始有timestamp.
9i可以用select systimestamp from dual;
42. NU{换ؓ(f)时分U格式？
set serverout on
declare
N number := 1000000;
ret varchar2(100);
begin
ret := trunc(n/3600) || '时' || to_char(to_date(mod(n,3600),'sssss'),'fmmi"?"ss"U?') ;
dbms_output.put_line(ret);
end;
43、在某个用户下找所有的索引
select user_indexes.table_name, user_indexes.index_name,uniqueness, column_name
from user_ind_columns, user_indexes
where user_ind_columns.index_name = user_indexes.index_name
and user_ind_columns.table_name = user_indexes.table_name
order by user_indexes.table_type, user_indexes.table_name,
user_indexes.index_name, column_position;
44. not in的替代?br /> 一般not in的效率比较低。特别是数据量大的时候，几乎不能执行?br /> 用下面几U方式可以替换写?br /> 比如要查询在fee_rev_info表中已经销L(fng)用户Q不在cm_user中的Q?不过下面的例子不是很好，因ؓ(f)bill_id是cm_user的唯一索引Q?br /> select * from fee_rev_info where bill_id not in (select bill_id from cm_user)
<1> 用not exists
select * from fee_rev_info a where not exists (select 'p' from cm_user b where b.bill_id = a.bill_id)
<2> 用外q接(+)
select a.* from fee_rev_info a,cm_user b
where a.bill_id = b.bill_id (+)
and b.bill_id is null
<3> 用hash_aj
select /*+HASH_AJ*/* from fee_rev_info where bill_id not in (select bill_id from cm_user)
45.怎么h询特D字W，如通配W?与_
假如数据库中有表 STATIONTYPE,STATION_571 STATION_572 ...
select * from tab where tname like 'STATION_%'
?x)显C?STATIONTYPE,STATION_571 ... 可以用下面的语句
select * from tab where tname like 'STATION\_%' escape'\'
46.如果存在更斎ͼ不存在就插入可以用一个语句实现吗
9i已经支持?jin)，是MergeQ但是只支持select子查询，
如果是单条数据记录，可以写作select .... from dual的子查询?br /> 语法为：(x)
MERGE INTO table
USING data_source
ON (condition)
WHEN MATCHED THEN update_clause
WHEN NOT MATCHED THEN insert_clause;
?br /> MERGE INTO cm_user_credit
USING (select * from dual) ON (user_id =1302514690 )
when MATCHED then update set credit_value = 1000
when NOT MATCHED then insert (user_id,acc_id,bill_id,plan_id,region_code,credit_value) values(1302514690,1305032158,'13857141218',10070247,'571',1000);
47.怎么实现一条记录根据条件多表插?br /> 9i以上可以通过Insert all语句完成Q仅仅是一个语句，如：(x)
INSERT ALL
WHEN (id=1) THEN
INTO table_1 (id, name)
values(id,name)
WHEN (id=2) THEN
INTO table_2 (id, name)
values(id,name)
ELSE
INTO table_other (id, name)
values(id, name)
SELECT id,name
FROM a;
如果没有条g的话Q则完成每个表的插入Q如
INSERT ALL
INTO table_1 (id, name)
values(id,name)
INTO table_2 (id, name)
values(id,name)
INTO table_other (id, name)
values(id, name)
SELECT id,name
FROM a;
48.如何实现行列转换
<1>、固定列数的行列转换
?br /> student subject grade
---------------------------
student1 语文 80
student1 数学 70
student1 p 60
student2 语文 90
student2 数学 80
student2 p 100
...
转换?
语文 数学 p
student1 80 70 60
student2 90 80 100
...
语句如下Q?br /> select student,sum(decode(subject,'语文', grade,null)) "语文",
sum(decode(subject,'数学', grade,null)) "数学",
sum(decode(subject,'p', grade,null)) "p"
from table
group by student
<2>、不定列行列转换
?br /> c1 c2
--------------
1 ?br /> 1 ?br /> 1 ?br /> 2 ?br /> 2 ?br /> 3 ?br /> ...
转换?br /> 1 我是?br /> 2 知道
3 ?br /> q一cd的{换必d助于PL/SQL来完成，q里l一个例?br /> CREATE OR REPLACE FUNCTION get_c2(tmp_c1 NUMBER)
RETURN VARCHAR2
IS
Col_c2 VARCHAR2(4000);
BEGIN
FOR cur IN (SELECT c2 FROM t WHERE c1=tmp_c1) LOOP
Col_c2 := Col_c2||cur.c2;
END LOOP;
Col_c2 := rtrim(Col_c2,1);
RETURN Col_c2;
END;
/
SQL> select distinct c1 ,get_c2(c1) cc2 from table;卛_
--例子Q?br /> create table okcai_1
(
user_id varchar2(10),
user_number varchar2(10),
user_num number(8)
)
user_id user_number user_num
---------------------
1 123 2
1 456 5
1 789 6
2 11 2
2 22 3
2 33 4
2 44 5
2 55 6
2 66 7
2 77 8
3 1234 1
3 5678 2
方式一Q?br /> create or replace function get_col(
p_userId number,
p_col number
) return varchar
as
v_tmp varchar2(255);
begin
select user_number||chr(9)||user_num into v_tmp
from
(select user_number,user_num,rownum row_id
from okcai_1
where user_id = p_userId) a
where row_id = p_col;
return ltrim(v_tmp);
--return v_tmp;
end;
然后
select distinct user_id,get_col(user_id,1),get_col(user_id,2),get_col(user_id,3) .... from okcai_1
方式二：(x)
create or replace function get_col(
p_userId number,
p_col number
) return varchar
as
v_tmp varchar2(255);
begin
select user_number||chr(9)||user_num into v_tmp
from
(select user_number,user_num,rownum row_id
from okcai_1
where user_id = p_userId) a
where row_id = p_col;
return ltrim(v_tmp);
--return v_tmp;
end;
select distinct user_id,get_col_new(user_id) from okcai_1;
49.怎么讄存储q程的调用者权?br /> 普通存储过E都是所有者权限，如果惌|调用者权限，请参考如下语?br /> create or replace
procedure ...()
AUTHID CURRENT_USER
As
begin
...
end;
50.Oracle有哪些常见关键字
详细信息可以查看v$reserved_words视图
51.怎么查看数据库参?br /> <1> show parameter 参数?br /> 如通过show parameter spfile可以查看9i是否使用spfile文g
其中参数名是可以匚w的?br /> 比如show parameter cursor ,则会(x)昄跟cursor相关的参?br /> <2>
select * from v$parameter
<3>
除了(jin)q部分参敎ͼOracleq有大量隐含参数Q可以通过如下语句查看:
SELECT NAME
,VALUE
,decode(isdefault, 'TRUE','Y','N') as "Default"
,decode(ISEM,'TRUE','Y','N') as SesMod
,decode(ISYM,'IMMEDIATE', 'I',
'DEFERRED', 'D',
'FALSE', 'N') as SysMod
,decode(IMOD,'MODIFIED','U',
'SYS_MODIFIED','S','N') as Modified
,decode(IADJ,'TRUE','Y','N') as Adjusted
,description
FROM ( --GV$SYSTEM_PARAMETER
SELECT x.inst_id as instance
,x.indx+1
,ksppinm as NAME
,ksppity
,ksppstvl as VALUE
,ksppstdf as isdefault
,decode(bitand(ksppiflg/256,1),1,'TRUE','FALSE') as ISEM
,decode(bitand(ksppiflg/65536,3),
1,'IMMEDIATE',2,'DEFERRED','FALSE') as ISYM
,decode(bitand(ksppstvf,7),1,'MODIFIED','FALSE') as IMOD
,decode(bitand(ksppstvf,2),2,'TRUE','FALSE') as IADJ
,ksppdesc as DESCRIPTION
FROM x$ksppi x
,x$ksppsv y
WHERE x.indx = y.indx
AND substr(ksppinm,1,1) = '_'
AND x.inst_id = USERENV('Instance')
)
ORDER BY NAME
52.怎样建立Z函数索引
8i以上版本Q确?br /> Query_rewrite_enabled=true
Query_rewrite_integrity=trusted
Compatible=8.1.0以上
Create index indexname on table (function(field));
53.怎么L(fng)动表或表分区
[A]Ud表的语法
Alter table tablename move
[Tablespace new_name
Storage(initial 50M next 50M
pctincrease 0 pctfree 10 pctused 50 initrans 2) nologging]
Ud分区的语?br /> alter table tablename move (partition partname)
[update global indexes]
之后之后必须重徏索引
Alter index indexname rebuild
如果表有LobD，那么正常的Alter不能UdLobD到别的表空_(d)而仅仅是Ud?jin)表D，可以采用如下的方法移动LobD?br /> alter table tablename move
lob(lobsegname) store as (tablespace newts);
54.怎么样修改表的列?br /> [A]9i以上版本可以采用rname命o(h)
ALTER TABLE UserName.TabName
RENAME COLUMN SourceColumn TO DestColumn
9i以下版本可以采用create table …?as select * from SourceTable的方式?br /> 另外Q?i以上可以支持删除列了(jin)
ALTER TABLE UserName.TabName
SET UNUSED (ColumnName) CASCADE CONSTRAINTS
ALTER TABLE UserName.TabName
DROP (ColumnName) CASCADE CONSTRAINTS
55.case的用?br /> 在sql语句?br /> CASE test_value
WHEN expression1 THEN value1
[[WHEN expression2 THEN value2] [...]]
[ELSE default_value]
END
比如1
SELECT last_name, job_id, salary
CASE job_id
WHEN 'IT_PROG' THEN 1.10*salary
WHEN 'ST_CLERK' THEN 1.15*salary
WHEN 'SA_REP' THEN 1.20*salary
ELSE salary END "REVISED_SALARY"
FROM employees
比如2
select
case
when real_charge>=20000 and real_charge<30000 then 5000
when real_charge>=30000 and real_charge<40000 then 9000
when real_charge>=40000 and real_charge<50000 then 10000
when real_charge>=50000 and real_charge<60000 then 14000
when real_charge>=60000 and real_charge<70000 then 18000
when real_charge>=70000 and real_charge<80000 then 19000
when real_charge>=80000 and real_charge<90000 then 24000
when real_charge>=90000 and real_charge<100000 then 27000
when real_charge>=100000 and real_charge<110000 then 27000
when real_charge>=110000 and real_charge<120000 then 29000
when real_charge>=120000 then 36000
else
0
end ,acc_id,user_id,real_charge from okcai_jh_charge_200505
在存储过E中
case v_strGroupClassCode
when '1' then
v_nAttrNum := v_nAttrNum + 300;
v_strAttrFlag := '1'||substr(v_strAttrFlag,2,7);
when '2' then
v_nAttrNum := v_nAttrNum + 200;
v_strAttrFlag := '2'||substr(v_strAttrFlag,2,7);
else
NULL;
end case;
注意的是存储q程和sql语句有的l微差别是用end caseQ而不是end。语句后面跟";"
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