Oracle SQL 內建函數的使用方法及結果

 SQL中的單記錄函數

1.ASCII 返回與指定的字元對應的十進位數;

SQL> select ascii('A') A,ascii('a') a,ascii('0') zero,ascii(' ') space from dual;

A A ZERO SPACE

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

65 97 48 32

 

2.CHR 給出整數,返回對應的字元;

SQL> select chr(54740) zhao,chr(65) chr65 from dual;

ZH C

-- -

趙 A

3.CONCAT 串連兩個字串;

SQL> select concat('010-','88888888')||'轉23' 高乾競電話 from dual;

高乾競電話

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

010-88888888轉23

4.INITCAP 返回字串並將字串的第一個字母變為大寫;

SQL> select initcap('smith') upp from dual;

UPP

-----

Smith

5.INSTR(C1,C2,I,J) 在一個字串中搜尋指定的字元,返回傳現指定的字元的位置;

C1 被搜尋的字串

C2 希望搜尋的字串

I 搜尋的開始位置,預設為1

J 出現的位置,預設為1

SQL> select instr('oracle traning','ra',1,2) instring from dual;

INSTRING

---------

9

6.LENGTH 返回字串的長度;

SQL> select name,length(name),addr,length(addr),sal,length(to_char(sal)) from .nchar_tst;

NAME LENGTH(NAME) ADDR LENGTH(ADDR) SAL LENGTH(TO_CHAR(SAL))

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

高乾競 3 北京市海錠區 6 9999.99 7

7.LOWER 返回字串,並將所有的字元小寫

SQL> select lower('AaBbCcDd')AaBbCcDd from dual;

AABBCCDD

--------

aabbccdd

8.UPPER 返回字串,並將所有的字元大寫

SQL> select upper('AaBbCcDd') upper from dual;

UPPER

--------

AABBCCDD

9.RPAD和LPAD(粘貼字元)

RPAD 在列的右邊粘貼字元

LPAD 在列的左邊粘貼字元

SQL> select lpad(rpad('gao',10,'*'),17,'*')from dual;

LPAD(RPAD('GAO',1

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

*******gao*******

不夠字元則用*來填滿

10.LTRIM和RTRIM

LTRIM 刪除左邊出現的字串

RTRIM 刪除右邊出現的字串

SQL> select ltrim(rtrim(' gao qian jing ',' '),' ') from dual;

LTRIM(RTRIM('

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

gao qian jing

11.SUBSTR(string,start,count)

取子字串,從start開始,取count個

SQL> select substr('13088888888',3,8) from dual;

SUBSTR('

--------

08888888

12.REPLACE('string','s1','s2')

string 希望被替換的字元或變數

s1 被替換的字串

s2 要替換的字串

SQL> select replace('he love you','he','i') from dual;

REPLACE('HELOVEYOU','HE','I')

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

i love you

13.SOUNDEX 返回一個與給定的字串讀音相同的字串

SQL> create table table1(xm varchar(8));

SQL> insert into table1 values('weather');

SQL> insert into table1 values('wether');

SQL> insert into table1 values('gao');

SQL> select xm from table1 where soundex(xm)=soundex('weather');

XM

--------

weather

wether

14.TRIM('s' from 'string')

LEADING 剪掉前面的字元

TRAILING 剪掉後面的字元

如果不指定,預設為空白格符

15.ABS 返回指定值的絕對值

SQL> select abs(100),abs(-100) from dual;

ABS(100) ABS(-100)

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

100 100

16.ACOS 給出反餘弦的值

SQL> select acos(-1) from dual;

ACOS(-1)

---------

3.1415927

17.ASIN 給出反正弦的值

SQL> select asin(0.5) from dual;

ASIN(0.5)

---------

.52359878

18.ATAN 返回一個數位反正切值

SQL> select atan(1) from dual;

ATAN(1)

---------

.78539816

19.CEIL 返回大於或等於給出數位最小整數

SQL> select ceil(3.1415927) from dual;

CEIL(3.1415927)

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

4

20.COS 返回一個給定數位餘弦

SQL> select cos(-3.1415927) from dual;

COS(-3.1415927)

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

-1

21.COSH 返回一個數字反餘弦值

SQL> select cosh(20) from dual;

COSH(20)

---------

242582598

22.EXP 返回一個數字e的n次方根

SQL> select exp(2),exp(1) from dual;

EXP(2) EXP(1)

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

7.3890561 2.7182818

23.FLOOR 對給定的數字取整數

SQL> select floor(2345.67) from dual;

FLOOR(2345.67)

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

2345

24.LN 返回一個數位對數值

SQL> select ln(1),ln(2),ln(2.7182818) from dual;

LN(1) LN(2) LN(2.7182818)

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

0 .69314718 .99999999

25.LOG(n1,n2) 返回一個以n1為底n2的對數

SQL> select log(2,1),log(2,4) from dual;

LOG(2,1) LOG(2,4)

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

0 2
 
26.MOD(n1,n2) 返回一個n1除以n2的餘數

SQL> select mod(10,3),mod(3,3),mod(2,3) from dual;

MOD(10,3) MOD(3,3) MOD(2,3)

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

1 0 2

27.POWER 返回n1的n2次方根

SQL> select power(2,10),power(3,3) from dual;

POWER(2,10) POWER(3,3)

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

1024 27

28.ROUND和TRUNC

按照指定的精度進行舍入

SQL> select round(55.5),round(-55.4),trunc(55.5),trunc(-55.5) from dual;

ROUND(55.5) ROUND(-55.4) TRUNC(55.5) TRUNC(-55.5)

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

56 -55 55 -55

29.SIGN 取數字n的符號,大於0返回1,小於0返回-1,等於0返回0

SQL> select sign(123),sign(-100),sign(0) from dual;

SIGN(123) SIGN(-100) SIGN(0)

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

1 -1 0

30.SIN 返回一個數位正弦值

SQL> select sin(1.57079) from dual;

SIN(1.57079)

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

1

31.SIGH 返回雙曲正弦的值

SQL> select sin(20),sinh(20) from dual;

 

SIN(20) SINH(20)

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

.91294525 242582598

32.SQRT 返回數字n的根

SQL> select sqrt(64),sqrt(10) from dual;

SQRT(64) SQRT(10)

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

8 3.1622777

33.TAN 返回數位正切值

SQL> select tan(20),tan(10) from dual;

TAN(20) TAN(10)

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

2.2371609 .64836083

34.TANH

返回數字n的雙曲正切值

SQL> select tanh(20),tan(20) from dual;

TANH(20) TAN(20)

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

1 2.2371609

35.TRUNC

按照指定的精度截取一個數

SQL> select trunc(124.1666,-2) trunc1,trunc(124.16666,2) from dual;

TRUNC1 TRUNC(124.16666,2)

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

100 124.16

36.ADD_MONTHS

增加或減去月份

SQL> select to_char(add_months(to_date('199912','yyyymm'),2),'yyyymm') from dual;

TO_CHA

------

200002

SQL> select to_char(add_months(to_date('199912','yyyymm'),-2),'yyyymm') from dual;

TO_CHA

------

199910

37.LAST_DAY

返回日期的最後一天

SQL> select to_char(sysdate,'yyyy.mm.dd'),to_char((sysdate)+1,'yyyy.mm.dd') from dual;

TO_CHAR(SY TO_CHAR((S

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

2004.05.09 2004.05.10

SQL> select last_day(sysdate) from dual;

LAST_DAY(S

----------

31-5月 -04

38.MONTHS_BETWEEN(date2,date1)

給出date2-date1的月份

SQL> select months_between('19-12月-1999','19-3月-1999') mon_between from dual;

MON_BETWEEN

-----------

9

SQL>selectmonths_between(to_date('2000.05.20','yyyy.mm.dd'),to_date('2005.05.20','yyyy.dd')) mon_betw from dual;

MON_BETW

---------

-60

39.NEW_TIME(date,'this','that')

給出在this時區=other時區的日期和時間

SQL> select to_char(sysdate,'yyyy.mm.dd hh24:mi:ss') bj_time,to_char(new_time

2 (sysdate,'PDT','GMT'),'yyyy.mm.dd hh24:mi:ss') los_angles from dual;

BJ_TIME LOS_ANGLES

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

2004.05.09 11:05:32 2004.05.09 18:05:32

40.NEXT_DAY(date,'day')

給出日期date和星期x之後計算下一個星期的日期

SQL> select next_day('18-5月-2001','星期五') next_day from dual;

NEXT_DAY

----------

25-5月 -01

41.SYSDATE 用來得到系統的當前日期

SQL> select to_char(sysdate,'dd-mm-yyyy day') from dual;

TO_CHAR(SYSDATE,'

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

09-05-2004 星期日

trunc(date,fmt)按照給出的要求將日期截斷,如果fmt='mi'表示保留分,截斷秒

SQL> select to_char(trunc(sysdate,'hh'),'yyyy.mm.dd hh24:mi:ss') hh,

2 to_char(trunc(sysdate,'mi'),'yyyy.mm.dd hh24:mi:ss') hhmm from dual;

HH HHMM

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

2004.05.09 11:00:00 2004.05.09 11:17:00

42.CHARTOROWID 將字元資料類型轉換為ROWID類型

SQL> select rowid,rowidtochar(rowid),ename from scott.emp;

ROWID ROWIDTOCHAR(ROWID) ENAME

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

AAAAfKAACAAAAEqAAA AAAAfKAACAAAAEqAAA SMITH

AAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLEN

AAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARD

AAAAfKAACAAAAEqAAD AAAAfKAACAAAAEqAAD JONES
 
 
43.CONVERT(c,dset,sset)

將源字串 sset從一個語言字元集轉換到另一個目的dset字元集

SQL> select convert('strutz','we8hp','f7dec') "conversion" from dual;

conver

------

strutz

44.HEXTORAW 將一個十六進位構成的字串轉換為二進位

45.RAWTOHEXT 將一個二進位構成的字串轉換為十六進位

46.ROWIDTOCHAR 將ROWID資料類型轉換為字元類型

47.TO_CHAR(date,'format')

SQL> select to_char(sysdate,'yyyy/mm/dd hh24:mi:ss') from dual;

TO_CHAR(SYSDATE,'YY

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

2004/05/09 21:14:41

48.TO_DATE(string,'format') 將字串轉化為ORACLE中的一個日期

49.TO_MULTI_BYTE 將字串中的單位元組字元轉化為多位元組字元

SQL> select to_multi_byte('高') from dual;

TO

--

高

50.TO_NUMBER

將給出的字元轉換為數字

SQL> select to_number('1999') year from dual;

YEAR

---------

1999

51.BFILENAME(dir,file) 指定一個外部二進位檔案

SQL>insert into file_tb1 values(bfilename('lob_dir1','image1.gif'));

52.CONVERT('x','desc','source') 將x欄位或變數的源source轉換為desc

SQL> select sid,serial#,username,decode(command,

2 0,'none',

3 2,'insert',

4 3,

5 'select',

6 6,'update',

7 7,'delete',

8 8,'drop',

9 'other') cmd from v$session where type!='background';

SID SERIAL# USERNAME CMD

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

1 1 none

2 1 none

3 1 none

4 1 none

5 1 none

6 1 none

7 1275 none

8 1275 none

9 20 GAO select

10 40 GAO none

53.DUMP(s,fmt,start,length)

DUMP函數以fmt指定的內部數字格式返回一個VARCHAR2類型的值

SQL> col global_name for a30

SQL> col dump_string for a50

SQL> set lin 200

SQL> select global_name,dump(global_name,1017,8,5) dump_string from global_name;

GLOBAL_NAME DUMP_STRING

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

ORACLE.WORLD Typ=1 Len=12 CharacterSet=ZHS16GBK: W,O,R,L,D

54.EMPTY_BLOB()和EMPTY_CLOB()

這兩個函數都是用來對大資料類型欄位進行初始化操作的函數

55.GREATEST

返回一組運算式中的最大值,即比較字元的編碼大小.

SQL> select greatest('AA','AB','AC') from dual;

GR

--

AC

SQL> select greatest('啊','安','天') from dual;

GR

--

天

56.LEAST

返回一組運算式中的最小值

SQL> select least('啊','安','天') from dual;

LE

--

啊

57.UID

返回標識目前使用者的唯一整數

SQL> show user

USER 為"GAO"

SQL> select username,user_id from dba_users where user_id=uid;

USERNAME USER_ID

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

GAO 25

58.USER

返回目前使用者的名字

SQL> select user from dual;

USER

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

GAO

59.USEREVN

返回目前使用者環境的資訊,opt可以是:

ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZE

ISDBA 查看目前使用者是否是DBA如果是則返回true

SQL> select userenv('isdba') from dual;

USEREN

------

FALSE

SQL> select userenv('isdba') from dual;

USEREN

------

TRUE

SESSION

返回會話標誌

SQL> select userenv('sessionid') from dual;

USERENV('SESSIONID')

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

152

ENTRYID

返回會話人口標誌

SQL> select userenv('entryid') from dual;

USERENV('ENTRYID')

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

0

INSTANCE

返回當前INSTANCE的標誌

SQL> select userenv('instance') from dual;

USERENV('INSTANCE')

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

1

LANGUAGE

返回當前環境變數

SQL> select userenv('language') from dual;

USERENV('LANGUAGE')

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

SIMPLIFIED CHINESE_CHINA.ZHS16GBK

LANG

返回當前環境的語言的縮寫

SQL> select userenv('lang') from dual;

USERENV('LANG')

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

ZHS

TERMINAL

返回使用者的終端或機器的標誌

SQL> select userenv('terminal') from dual;

USERENV('TERMINA

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

GAO

VSIZE(X)

返回X的大小(位元組)數

SQL> select vsize(user),user from dual;

VSIZE(USER) USER

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

6 SYSTEM

60.AVG(DISTINCT|ALL) 

all表示對所有的值求平均值,distinct只對不同的值求平均值

SQLWKS> create table table3(xm varchar(8),sal number(7,2));

語句已處理。

SQLWKS> insert into table3 values('gao',1111.11);

SQLWKS> insert into table3 values('gao',1111.11);

SQLWKS> insert into table3 values('zhu',5555.55);

SQLWKS> commit;

SQL> select avg(distinct sal) from gao.table3;

AVG(DISTINCTSAL)

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

3333.33

SQL> select avg(all sal) from gao.table3;

AVG(ALLSAL)

-----------

2592.59

61.MAX(DISTINCT|ALL) 

求最大值,ALL表示對所有的值求最大值,DISTINCT表示對不同的值求最大值,相同的只取一次

SQL> select max(distinct sal) from scott.emp;

 

MAX(DISTINCTSAL)

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

5000

62.MIN(DISTINCT|ALL) 

求最小值,ALL表示對所有的值求最小值,DISTINCT表示對不同的值求最小值,相同的只取一次

SQL> select min(all sal) from gao.table3;

MIN(ALLSAL)

-----------

1111.11

63.STDDEV(distinct|all) 

求標準差,ALL表示對所有的值求標準差,DISTINCT表示只對不同的值求標準差

SQL> select stddev(sal) from scott.emp;

STDDEV(SAL)

-----------

1182.5032

SQL> select stddev(distinct sal) from scott.emp;

STDDEV(DISTINCTSAL)

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

1229.951

64.VARIANCE(DISTINCT|ALL) 求共變數

SQL> select variance(sal) from scott.emp;

VARIANCE(SAL)

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

1398313.9

65.GROUP BY 主要用來對一組數進行統計

SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno;

DEPTNO COUNT(*) SUM(SAL)

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

10 3 8750

20 5 10875

30 6 9400

66.HAVING 對分組統計再加限制條件

SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno having nt(*)>=5;

DEPTNO COUNT(*) SUM(SAL)

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

20 5 10875

30 6 9400

SQL> select deptno,count(*),sum(sal) from scott.emp having count(*)>=5 group by tno ;

DEPTNO COUNT(*) SUM(SAL)

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

20 5 10875

30 6 9400

67.ORDER BY 用於對查詢到的結果進行排序輸出

SQL> select deptno,ename,sal from scott.emp order by deptno,sal desc;

DEPTNO ENAME SAL

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

10 KING 5000

10 CLARK 2450

10 MILLER 1300

20 SCOTT 3000

20 FORD 3000

20 JONES 2975

20 ADAMS 1100

20 SMITH 800

30 BLAKE 2850

30 ALLEN 1600

30 TURNER 1500

30 WARD 1250

30 MARTIN 1250

30 JAMES 950