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SQL 21 天自学通学习笔�?5

javalinjx — Sun, 05 Aug 2012 03:44:00 GMT

1. 用户操作�Q?/p>

创徏�Q?/p>

CREATE USER user
IDENTIFIED {BY password | EXTERNALLY}
[DEFAULT TABLESPACE tablespace]
[TEMPORARY TABLESPACE tablespace]
[QUOTA {integer [K|M] | UNLIMITED} ON tablespace]
[PROFILE profile]

修改�Q?/p>

ALTER USER user  
[IDENTIFIED {BY password | EXTERNALLY}]  
[DEFAULT TABLESPACE tablespace]  
[TEMPORARY TABLESPACE tablespace]  
[QUOTA {integer [K|M] | UNLIMITED} ON tablespace]  
[PROFILE profile]  
[DEFAULT ROLE { role [, role] ...  
| ALL [EXCEPT role [, role] ...] | NONE}]  

删除�Q?/p>

DROP USER user_name [CASCADE]

授权�Q�撤销权限�Q?/p>

GRANT role TO user [WITH ADMIN OPTION]  
  
REVOKE role FROM user  

�pȝ��允许赋于整个�pȝ��的权限给用户�Q�角色等�Q?/p>

GRANT system_privilege TO {user_name | role | PUBLIC}
[WITH ADMIN OPTION]

如果使用了WITH ADMIN OPTION 选项��允许拥有该权限的�h��该权限应用�l�其�?/p>

的用戗��?/p>

你可以��用下边的GRANT 语句来对其它用户授权讉K��你的�?/p>

GRANT {object_priv | ALL [PRIVILEGES]} [ (column  
[, column]...) ]  
[, {object_priv | ALL [PRIVILEGES]} [ (column  
[, column] ...) ] ] ...  
ON [schema.]object  
TO {user | role | PUBLIC} [, {user | role | PUBLIC}] ...  
[WITH GRANT OPTION]  

如果你想取消�Ҏ��个对象对于某人的授权你可以��用REVOKE 语句语法如下

REVOKE {object_priv | ALL [PRIVILEGES]}  
[, {object_priv | ALL [PRIVILEGES]} ]  
ON [schema.]object  
FROM {user | role | PUBLIC} [, {user | role | PUBLIC}]  
[CASCADE CONSTRAINTS]  

javalinjx 2012-08-05 11:44 发表评论

SQL 21 天自学通学习笔�?4

javalinjx — Sun, 05 Aug 2012 03:23:00 GMT

1. insert select 用法�Q?/p>

insert into tablename1 (col1,col2)

select col1,col2 from tablename2 ;

2. 删除表：

drop table ovner.tablename;

3. 创徏视图�Q?/p>

CREATE VIEW [(column1, column2...)] AS

SELECT

FROM

在视囄��select 语句中��用约束是必然的，在��用select 语句中可以应用下边两个规则：

a. 不能使用union操作�Q?/p>

b. 不能使用order by 子句但是在视图中使用group by 子句可以有order by 子句相同的功能；

�q�要注意�Q?. 对于多表视图你不能��用delete 语句�Q?.除非底层表的所有非�I�列都已�l�在视图�?/p>

出现�Q�否则你不能使用insert语句�Q?/p>

4. 索引 index:

CREATE INDEX index_name ON table_name(column_name1, [column_name2], ...)

CREATE INDEX [schema.]index ON { [schema.]table (column [!!under!!ASC|DESC] [, column [!!under!!ASC|DESC]] ...) | CLUSTER [schema.]cluster }

当表被删除时�Q�所有与表相关的索引也将被删�?

javalinjx 2012-08-05 11:23 发表评论

SQL 21 天自学通学习笔�?3

javalinjx — Sun, 17 Jun 2012 14:47:00 GMT

1. STARTING WITH 子句相当于like (**%);

2. order by 子句

3. group by 子句

4. having 子句

SQL> select team,avg(sickleave),avg(annualleave) from orgchart

2 group by team

3 having avg(sickleave)>25 and avg(annualleave)<20;

TEAM AVG(SICKLEAVE) AVG(ANNUALLEAVE)

--------------- -------------- ----------------

RESEARCH 27 14.5

MARKETING 28.33333333333 15.3333333333333

SQL> select * from orgchart;

NAME TEAM SALARY SICKLEAVE ANNUALLEAVE

--------------- --------------- ------------ --------- -----------

ADAMS RESEARCH 34000.00 34 12

WILKES MARKETING 31000.00 40 9

STOKES MARKETING 36000.00 20 19

MEZA COLLECTIONS 40000.00 30 27

MERRICK RESEARCH 45000.00 20 17

RICHARDSON MARKETING 42000.00 25 18

FURY COLLECTIONS 35000.00 22 14

PRECOURT PR 37500.00 24 24

8 rows selected

SQL> select team,avg(sickleave),avg(annualleave) from orgchart

2 group by team having count (team)>1;

TEAM AVG(SICKLEAVE) AVG(ANNUALLEAVE)

--------------- -------------- ----------------

COLLECTIONS 26 20.5

RESEARCH 27 14.5

MARKETING 28.33333333333 15.3333333333333

SQL> select team,avg(salary)from orgchart

2 group by team having team in ('PR','RESEARCH');

TEAM AVG(SALARY)

--------------- -----------

PR 37500

RESEARCH 39500

5. 两者结合��用：

SQL> select * from orgchart order by name desc;

NAME TEAM SALARY SICKLEAVE ANNUALLEAVE

--------------- --------------- ------------ --------- -----------

WILKES MARKETING 31000.00 40 9

STOKES MARKETING 36000.00 20 19

RICHARDSON MARKETING 42000.00 25 18

PRECOURT PR 37500.00 24 24

MEZA COLLECTIONS 40000.00 30 27

MERRICK RESEARCH 45000.00 20 17

FURY COLLECTIONS 35000.00 22 14

ADAMS RESEARCH 34000.00 34 12

8 rows selected

SQL> select payee,sum(amount)total,count(payee)number_written from checks

2 group by payee having sum(amount) > 50;

PAYEE TOTAL NUMBER_WRITTEN

------------------------------------ ---------- --------------

Ma Bell 350.32 2

Reading R.R. 245.34 1

Local Utilities 98 1

Joes Stale$ Dent 150 1

SQL> select payee,sum(amount) total,count(payee)number_written

2 from checks where amount >= 100 group by payee

3 having sum(amount) > 50;

PAYEE TOTAL NUMBER_WRITTEN

------------------------------------ ---------- --------------

Ma Bell 350.32 2

Reading R.R. 245.34 1

Joes Stale$ Dent 150 1

where 子句与order by子句常在对单行进行处理时用到�Q?/p>

group by �?having子句常用在对数据�q�行汇��L��作上�?/p>

javalinjx 2012-06-17 22:47 发表评论

SQL 21 天自学通学习笔�?2

javalinjx — Sun, 17 Jun 2012 14:46:00 GMT

摘要: 日期、时间函敎ͼ� select * from project; 针对日期型： 1. add_months: 增加月䆾 select * from task,startdate,enddate,original_end,add_months(enddate,2) from project; se... 阅读全文

javalinjx 2012-06-17 22:46 发表评论

SQL 21 天自学通学习笔�?1

javalinjx — Sun, 17 Jun 2012 14:44:00 GMT

中午又看了一下汇��d��敎ͼ�

count ,sum,avg,max,min,variance(方差),stddev

1. SELECT COUNT( ) FROM TEAMSTATS WHERE HITS/AB .35;

2. SELECT SUM(SINGLES) TOTAL_SINGLES FROM TEAMSTATS; //不能处理字符�?/p>

3. SELECT AVG(SO) AVE_STRIKE_OUTS FROM TEAMSTATS; //不能处理字符�?/p>

4. SELECT MAX(HITS) FROM TEAMSTATS;

5. SELECT MIN(AB) FROM TEAMSTATS;

6. SELECT VARIANCE(HITS) FROM TEAMSTATS; //不能处理字符�?/p>

7. SELECT STDDEV(HITS) FROM TEAMSTATS; //不能处理字符�?/p>

8. SELECT COUNT AB AVG(AB) MIN(AB) MAX(AB) STDDEV(AB)

VARIANCE(AB) SUM(AB) FROM TEAMSTATS;

注意�Q�汇��d��C��能放在where子句中��用，持箋更新。�?/p>

javalinjx 2012-06-17 22:44 发表评论

javalinjx — Wed, 13 Jun 2012 00:50:00 GMT

今天�l�箋学习sql�Q�此前都没有�pȝ��的学习下sql的写法，关键是应用的比较��，才导致sql的水�q�_��在不敢冒险；

现在学习�q�个�Q�记录一些个��得有用的语句�Q�或者个��Z��懂的�Q?/p>

1. MINUS: 对减�Q�查询表A中有�Q�表B中没有的记录�Q?/p>

SELECT * FROM FOOTBALL MINUS SELECT * FROM SOFTBALL

2. 从属�q�算�Q�in or between

SELECT * FROM PRICE WHERE WHOLESALE BETWEEN 0.25 AND 0.75

如果批发价�ؓ0.25 的商品在表中存在那么它们也将会被�q�回BETWEEN 操作��包

括边界倹{�?/p>

javalinjx 2012-06-13 08:50 发表评论