oracle 10g

1创建新表

  1.1从查询到的表创建表

  create table temp as select stuName,stuNo,stuSex from stuInfo where stuAge>25;

  1.2创建新表

  /*学生信息表*/

  create table stuInfo(

  stuName varchar2(10) ,

  stuNo varchar2(10),

  stuSex varchar2(4),

  stuAge number(2),

  stuSeat number(10),

  stuAddress varchar2(400));

  /*学生成绩表*/

  create table stuMark(

  examNo varchar2(10),

  stuNo varchar2(10),

  writtenExam number(4),

  labExam number(4));

  2 修改表

  2.1 增加字段

  alter table stuInfo add(Zip number(6));

  2.2 删除字段

  alter table stuInfo drop column Zip

  2.3 修改字段类型

  alter table stuInfo modify(Zip varchar2(6));

  2.4修改字段大小

  alter table stuInfo modify(Zip number(4));

  2.5 删除表

  drop table stuInfo

  3约束

  3.1添加约束

  alter table stuInfo add constraint PK_stuNo primary key(stuNo);

  alter table stuInfo add constraint CK_stuSex check(stuSex in('男','女'));

  alter table stuInfo add constraint CK_stuAge check(stuAge between 15 and 40);

  alter table stuInfo add constraint CK_stuSeat check(stuSeat between 1 and 30);

  alter table stuMark add constraint PK_ExamNo_stuMark primary key(examNo);

  alter table stuMark add constraint FK_stuNo_stuMark foreign key(stuNo) references stuInfo(stuNo);

  select stuName,decode(stuSex,'男','男同志'),

  (stuSex,'女','女同志')

  from stuInfo;

  alter table stuInfo modify(stuSex not null);

  3.2删除约束

  3.2.1删除普通约束

  alter table stuInfo drop constraint CK_stuSex;

  3.2.2删除被外键参照的主键约束

  alter table stuInfo drop primary key PK_StuNo

  4索引

  4.1创建索引

  create index stuName_index on stuInfo(stuName);

  4.2删除索引

  drop index stuName_index;

  5创建序列

  5.1 创建序列

  create sequence stuSeat_identity

  minvalue 1

  maxvalue 99999999

  start with 1

  increment by 1

  cache 2

  5.2触发器实现字段列自增长

  create table stu(

  stuID number(10),

  stuName varchar2(20));

  create sequence autoId start with 1 increment by 1 cache 200;

  create or replace trigger getautoId

  before insert on stu

  for each row

  declare

  -- local variables here

  begin

  select autoId.Nextval into :new.stuId from dual;

  end getautoId;

  insert into stu values(null,'s');

  insert into stu values(null,'s1');

  insert into stu values(null,'s2');

  insert into stu values(null,'s3');

  6视图

  6.1 创建视图

  create or replace view v_stuInfo as select * from stuInfo;

  6.2 删除视图

  drop view v_stuInfo;

  7同义词

  7.1 创建同义词

  create synonym st for System.stuInfo;

  7.2 删除同义词

  drop synonym st;

  8 数据操作语句

  8.1 插入数据

  insert into stuInfo values('MARK','s25301','男',18,stuseat_identity.nextval,'北京海淀');

  insert into stuInfo values('andy','s25303','女',22,stuseat_identity.nextval,'河南洛阳');

  insert into stuInfo values('JACK','s25302','男',31,stuseat_identity.nextval,'武汉武昌');

  insert into stuInfo values('zerolin','s25304','男',28,stuseat_identity.nextval,'新疆威武哈');

  insert into stuMark values('s271811','s25303',90,56);

  insert into stuMark values('s271813','s25302',58,90);

  insert into stuMark values('s271816','s25301',87,82);

  insert into stuMark values('s271819','s25304',66,48);

  8.2 更新语句

  update stuInfo set stuName='Oracle' where stuAge>27;

  8.3 数据合拼语句

  merge into depat_13_temp a

  using department_13 b

  on(a.department_id = b.department_id)

  when matched then

  update set

  a.department_name = b.department_name,

  a.manager_id = b.manager_id,

  a.location_id = b.location_id

  when not matched then

  insert(a.department_id, a.department_name, a.manager_id, a.location_id)

  values(b.department_id, b.department_name, b.manager_id, b.location_id);

  9 查询语句

  9.1 带算术表达式的select语句

  select ExamNo,stuNo,writtenExam,labExam+100 from stuMark;

  9.2 带连接表达式的select语句

  select ExamNo||'的学号是:'||stuNo||'笔记成绩是:'||writtenExam||'机试成绩是:'||labExam from stuMark;

  9.3 字段别名

  select ExamNo "考号",stuNo "学号",writtenExam "笔记成绩是",labExam "机试成绩是" from stuMark;

  9.4 比较操作符

  between..and

  in

  like

  is null

  9.5 比较操作的逻辑运算符

  and or

  select * from stuInfo where stuSex='男' or stuSex='女';

select * from stuInfo where stuSex='男' and stuAge>27;

 

在oracle中处理日期大全

 

TO_DATE格式

Day:

dd number 12

dy abbreviated fri

day spelled out friday

ddspth spelled out, ordinal twelfth

Month:

mm number 03

mon abbreviated mar

month spelled out march

Year:

yy two digits 98

yyyy four digits 1998

 

24小时格式下时间范围为: 0:00:00 - 23:59:59....

12小时格式下时间范围为: 1:00:00 - 12:59:59 ....

1.

日期和字符转换函数用法(to_date,to_char)

 

2.

select to_char( to_date(222,'J'),'Jsp') from dual

 

显示Two Hundred Twenty-Two

 

3. 求某天是星期几

Select to_char(to_date('2002-08-26','yyyy-mm-dd'),'day') from dual;

星期一

select to_char(to_date('2002-08-26','yyyy-mm-dd'),'day','NLS_DATE_LANGUAGE = American') from dual;

monday

设置日期语言

ALTER SESSION SET NLS_DATE_LANGUAGE='AMERICAN';

也可以这样

TO_DATE ('2002-08-26', 'YYYY-mm-dd', 'NLS_DATE_LANGUAGE = American')

 

4. 两个日期间的天数

select floor(sysdate - to_date('20020405','yyyymmdd')) from dual;

 

5. 时间为null的用法

select id, active_date from table1

UNION

select 1, TO_DATE(null) from dual;

 

注意要用TO_DATE(null)

 

6.

a_date between to_date('20011201','yyyymmdd') and to_date('20011231','yyyymmdd')

那么12月31号中午12点之后和12月1号的12点之前是不包含在这个范围之内的。

所以,当时间需要精确的时候,觉得to_char还是必要的

7. 日期格式冲突问题

输入的格式要看你安装的ORACLE字符集的类型, 比如: US7ASCII, date格式的类型就是: '01-Jan-01'

alter system set NLS_DATE_LANGUAGE = American

alter session set NLS_DATE_LANGUAGE = American

或者在to_date中写

select to_char(to_date('2002-08-26','yyyy-mm-dd'),'day','NLS_DATE_LANGUAGE = American') from dual;

注意我这只是举了NLS_DATE_LANGUAGE,当然还有很多,

可查看

select * from nls_session_parameters

select * from V$NLS_PARAMETERS

 

8.

select count(*)

from ( select rownum-1 rnum

from all_objects

where rownum <= to_date('2002-02-28','yyyy-mm-dd') - to_date('2002-

02-01','yyyy-mm-dd')+1

)

where to_char( to_date('2002-02-01','yyyy-mm-dd')+rnum-1, 'D' )

not

in ( '1', '7' )

 

查找2002-02-28至2002-02-01间除星期一和七的天数

在前后分别调用DBMS_UTILITY.GET_TIME, 让后将结果相减(得到的是1/100秒, 而不是毫秒).

 

9.

select months_between(to_date('01-31-1999','MM-DD-YYYY'),

to_date('12-31-1998','MM-DD-YYYY')) "MONTHS" FROM DUAL;

1

 

select months_between(to_date('02-01-1999','MM-DD-YYYY'),

to_date('12-31-1998','MM-DD-YYYY')) "MONTHS" FROM DUAL;

 

1.03225806451613

10. Next_day的用法

Next_day(date, day)

 

Monday-Sunday, for format code DAY

Mon-Sun, for format code DY

1-7, for format code D

 

11 select to_char(sysdate,'hh:mi:ss') TIME from all_objects

注意:第一条记录的TIME 与最后一行是一样的

可以建立一个函数来处理这个问题

create or replace function sys_date return date is

begin

return sysdate;

end;

 

select to_char(sys_date,'hh:mi:ss') from all_objects;

12. 获得小时数

 

SELECT EXTRACT(HOUR FROM TIMESTAMP '2001-02-16 2:38:40') from offer

SQL> select sysdate ,to_char(sysdate,'hh') from dual;

 

SYSDATE TO_CHAR(SYSDATE,'HH')

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

2003-10-13 19:35:21 07

 

SQL> select sysdate ,to_char(sysdate,'hh24') from dual;

 

SYSDATE TO_CHAR(SYSDATE,'HH24')

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

2003-10-13 19:35:21 19

 

13. 年月日的处理

select older_date,

newer_date,

years,

months,

abs(

trunc(

newer_date-

add_months( older_date,years*12+months )

)

) days

from ( select

trunc(months_between( newer_date, older_date )/12) YEARS,

mod(trunc(months_between( newer_date, older_date )),

12 ) MONTHS,

newer_date,

older_date

from ( select hiredate older_date,

add_months(hiredate,rownum)+rownum newer_date

from emp )

)

 

14. 处理月份天数不定的办法

select to_char(add_months(last_day(sysdate) +1, -2), 'yyyymmdd'),last_day(sysdate) from dual

 

16. 找出今年的天数

select add_months(trunc(sysdate,'year'), 12) - trunc(sysdate,'year') from dual

 

闰年的处理方法

to_char( last_day( to_date('02' || :year,'mmyyyy') ), 'dd' )

如果是28就不是闰年

 

17. yyyy与rrrr的区别

'YYYY99 TO_C

------- ----

yyyy 99 0099

rrrr 99 1999

yyyy 01 0001

rrrr 01 2001

 

18.不同时区的处理

select to_char( NEW_TIME( sysdate, 'GMT','EST'), 'dd/mm/yyyy hh:mi:ss') ,sysdate

from dual;

 

19. 5秒钟一个间隔

Select TO_DATE(FLOOR(TO_CHAR(sysdate,'SSSSS')/300) * 300,'SSSSS') ,TO_CHAR(sysdate,'SSSSS')

from dual

 

2002-11-1 9:55:00 35786

SSSSS表示5位秒数

 

20. 一年的第几天

select TO_CHAR(SYSDATE,'DDD'),sysdate from dual

310 2002-11-6 10:03:51

 

21.计算小时,分,秒,毫秒

select

Days,

A,

TRUNC(A*24) Hours,

TRUNC(A*24*60 - 60*TRUNC(A*24)) Minutes,

TRUNC(A*24*60*60 - 60*TRUNC(A*24*60)) Seconds,

TRUNC(A*24*60*60*100 - 100*TRUNC(A*24*60*60)) mSeconds

from

(

select

trunc(sysdate) Days,

sysdate - trunc(sysdate) A

from dual

)

 

 

 

select * from tabname

order by decode(mode,'FIFO',1,-1)*to_char(rq,'yyyymmddhh24miss');

 

//

floor((date2-date1) /365) 作为年

floor((date2-date1, 365) /30) 作为月

mod(mod(date2-date1, 365), 30)作为日.

23.next_day函数

next_day(sysdate,6)是从当前开始下一个星期五。后面的数字是从星期日开始算起。

1 2 3 4 5 6 7

日 一 二 三 四 五 六

 

 

 

 

oracle中有很多关于日期的函数

 

在oracle中有很多关于日期的函数,如:

1、add_months()用于从一个日期值增加或减少一些月份

date_value:=add_months(date_value,number_of_months)

例:

SQL> select add_months(sysdate,12) "Next Year" from dual;

 

Next Year

----------

13-11月-04

 

SQL> select add_months(sysdate,112) "Last Year" from dual;

 

Last Year

----------

13-3月 -13

 

SQL>

 

2、current_date()返回当前会放时区中的当前日期

date_value:=current_date

SQL> column sessiontimezone for a15

SQL> select sessiontimezone,current_date from dual;

 

SESSIONTIMEZONE CURRENT_DA

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

+08:00 13-11月-03

 

SQL> alter session set time_zone='-11:00'

2 /

 

会话已更改。

 

SQL> select sessiontimezone,current_timestamp from dual;

 

SESSIONTIMEZONE CURRENT_TIMESTAMP

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

-11:00 12-11月-03 04.59.13.668000 下午 -11:

                00

 

SQL>

 

3、current_timestamp()以timestamp with time zone数据类型返回当前会放时区中的当前日期

timestamp_with_time_zone_value:=current_timestamp([timestamp_precision])

SQL> column sessiontimezone for a15

SQL> column current_timestamp format a36

SQL> select sessiontimezone,current_timestamp from dual;

 

SESSIONTIMEZONE CURRENT_TIMESTAMP

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

+08:00 13-11月-03 11.56.28.160000 上午 +08:

                00

 

SQL> alter session set time_zone='-11:00'

2 /

 

会话已更改。

 

SQL> select sessiontimezone,current_timestamp from dual;

 

SESSIONTIMEZONE CURRENT_TIMESTAMP

-11:00 12-11月-03 04.58.00.243000 下午 -11:

                00

 

SQL>

 

4、dbtimezone()返回时区

varchar_value:=dbtimezone

SQL> select dbtimezone from dual;

 

DBTIME

------

-07:00

 

SQL>

 

5、extract()找出日期或间隔值的字段值

date_value:=extract(date_field from [datetime_value|interval_value])

SQL> select extract(month from sysdate) "This Month" from dual;

 

This Month

----------

        11

 

SQL> select extract(year from add_months(sysdate,36)) "3 Years Out" from dual;

 

3 Years Out

-----------

       2006

 

SQL>

 

6、last_day()返回包含了日期参数的月份的最后一天的日期

date_value:=last_day(date_value)

SQL> select last_day(date'2000-02-01') "Leap Yr?" from dual;

 

Leap Yr?

----------

29-2月 -00

 

SQL> select last_day(sysdate) "Last day of this month" from dual;

 

Last day o

----------

30-11月-03

 

SQL>

 

7、localtimestamp()返回会话中的日期和时间

timestamp_value:=localtimestamp

SQL> column localtimestamp format a28

SQL> select localtimestamp from dual;

 

LOCALTIMESTAMP

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

13-11月-03 12.09.15.433000

下午

 

SQL> select localtimestamp,current_timestamp from dual;

 

LOCALTIMESTAMP CURRENT_TIMESTAMP

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

13-11月-03 12.09.31.006000 13-11月-03 12.09.31.006000 下午 +08:

下午 00

 

SQL> alter session set time_zone='-11:00';

 

会话已更改。

 

SQL> select localtimestamp,to_char(sysdate,'DD-MM-YYYY HH:MI:SS AM') "SYSDATE" from dual;

 

LOCALTIMESTAMP SYSDATE

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

12-11月-03 05.11.31.259000 13-11-2003 12:11:31 下午

下午

 

SQL>

 

8、months_between()判断两个日期之间的月份数量

number_value:=months_between(date_value,date_value)

SQL> select months_between(sysdate,date'1971-05-18') from dual;

 

MONTHS_BETWEEN(SYSDATE,DATE'1971-05-18')

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

                              389.855143

 

SQL> select months_between(sysdate,date'2001-01-01') from dual;

 

MONTHS_BETWEEN(SYSDATE,DATE'2001-01-01')

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

                              34.4035409

 

SQL>

 

9、next_day()给定一个日期值,返回由第二个参数指出的日子第一次出现在的日期值(应返回相应日子的名称字符串)

 

1.查询某周的第一天

select trunc(decode(ww, 53, to_date(yy || '3112', 'yyyyddmm'), to_date(yy || '-' || to_char(ww * 7), 'yyyy-ddd')), 'd') last_day

from (select substr('2004-32', 1, 4) yy, to_number(substr('2004-32', 6)) ww

         from dual)

 

select trunc(to_date(substr('2003-01',1,5)||to_char((to_number(substr('2003-01',6)))*7),'yyyy-ddd'),'d')-6 first_day from dual

 

select min(v_date) from

(select (to_date('200201','yyyymm') + rownum) v_date

from all_tables

where rownum < 370)

where to_char(v_date,'yyyy-iw') = '2002-49'

 

2.查询某周的最后一天

select trunc(decode(ww, 53, to_date(yy || '3112', 'yyyyddmm'), to_date(yy || '-' || to_char(ww * 7), 'yyyy-ddd')), 'd') - 6 first_day

from (select substr('2004-33', 1, 4) yy, to_number(substr('2004-33', 6)) ww

          from dual)

         

select trunc(to_date(substr('2003-01',1,5)||to_char((to_number(substr('2003-01',6)))*7),'yyyy-ddd'),'d') last_day from dual

 

select max(v_date) from

(select (to_date('200408','yyyymm') + rownum) v_date

from all_tables

where rownum < 370)

where to_char(v_date,'yyyy-iw') = '2004-33'

 

3.查询某周的日期

select min_date, to_char(min_date,'day') day from

(select to_date(substr('2004-33',1,4)||'001'+rownum-1,'yyyyddd') min_date

        from all_tables

where rownum <= decode(mod(to_number(substr('2004-33',1,4)),4),0,366,365)

union

 

select to_date(substr('2004-33',1,4)-1||

         decode(mod(to_number(substr('2004-33',1,4))-1,4),0,359,358)+rownum,'yyyyddd') min_date

        from all_tables         

          where rownum <= 7

union

 

select to_date(substr('2004-33',1,4)+1||'001'+rownum-1,'yyyyddd') min_date

        from all_tables         

          where rownum <= 7                      

)

where to_char(min_date,'yyyy-iw') ='2004-33'

 

 

 

 

oracle中时间运算

 

论坛中常常看到有对oracle中时间运算提问的问题,今天有时间,看了看以前各位兄弟的贴子,整理了一下,并作了个示例,希望会对大家有帮助。

首先感谢ern、eric.li及各版主还有热心的兄弟们

 

内容如下:

1、oracle支持对日期进行运算

2、日期运算时是以天为单位进行的

3、当需要以分秒等更小的单位算值时,按时间进制进行转换即可

4、进行时间进制转换时注意加括号(见示例中红色括号),否则会出问题

 

SQL> alter session set nls_date_format='yyyy-mm-dd hh:mi:ss';

 

会话已更改。

 

SQL> set serverout on

SQL> declare

DateValue date;

   begin

select sysdate into DateValue from dual;

   dbms_output.put_line('源时间:'||to_char(DateValue));

dbms_output.put_line('源时间减1天:'||to_char(DateValue-1));

dbms_output.put_line('源时间减1天1小时:'||to_char(DateValue-1-1/24));

dbms_output.put_line('源时间减1天1小时1分:'||to_char(DateValue-1-1/24-1/(24*60)));

dbms_output.put_line('源时间减1天1小时1分1秒:'||to_char(DateValue-1-1/24-1/(24*60)-1/(24*60*6 0)));

end;

源时间:2003-12-29 11:53:41

源时间减1天:2003-12-28 11:53:41

源时间减1天1小时:2003-12-28 10:53:41

源时间减1天1小时1分:2003-12-28 10:52:41

源时间减1天1小时1分1秒:2003-12-28 10:52:40

关于Oracle取整的函数分别有以下几种:

  1.取整(大)
  select ceil(-1.001) value from dual

  2.取整(小)
  select floor(-1.001) value from dual

  3.取整(截取)
  select trunc(-1.002) value from dual

       4.取整(舍入)
       select round(-1.001) value from dual

 

声明:本文来自 http://hi.baidu.com/erhsh_165/blog/item/b91ee1fa52cc83839e514642.html

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