ORACLE函數大全

SQL中的單記錄函數
1.ASCII
返回與指定的字符對應的十進制數;
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,返回對應的字符;
SQL> select chr(54740) zhao,chr(65) chr65 from dual;
ZH C

---

趙 A
3.CONCAT
連接兩個字符串;
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
返回字符串並將字符串的第一個字母變爲大寫;
SQL> select initcap(‘smith’) upp from dual;

UPP

Smith

5.INSTR(C1,C2,I,J)
在一個字符串中搜索指定的字符,返回發現指定的字符的位置;
C1 被搜索的字符串
C2 希望搜索的字符串
I 搜索的開始位置,默認爲1
J 出現的位置,默認爲1
SQL> select instr(‘oracle traning’,’ra’,1,2) instring from dual;

INSTRING

    9

6.LENGTH
返回字符串的長度;
SQL> select name,length(name),addr,length(addr),sal,length(to_char(sal)) from gao.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
返回字符串,並將所有的字符小寫
SQL> select lower(‘AaBbCcDd’)AaBbCcDd from dual;

AABBCCDD

aabbccdd

8.UPPER
返回字符串,並將所有的字符大寫
SQL> select upper(‘AaBbCcDd’) upper from dual;

UPPER

AABBCCDD

9.RPAD和LPAD(粘貼字符)
RPAD 在列的右邊粘貼字符
LPAD 在列的左邊粘貼字符
SQL> select lpad(rpad(‘gao’,10,’‘),17,’‘)from dual;

LPAD(RPAD(‘GAO’,1

**gao**
不夠字符則用*來填滿

10.LTRIM和RTRIM
LTRIM 刪除左邊出現的字符串
RTRIM 刪除右邊出現的字符串
SQL> select ltrim(rtrim(’ gao qian jing ‘,’ ‘),’ ‘) from dual;

LTRIM(RTRIM(‘

gao qian jing

11.SUBSTR(string,start,count)
取子字符串,從start開始,取count個
SQL> select substr(‘13088888888’,3,8) from dual;

SUBSTR(‘

08888888

12.REPLACE(‘string’,’s1’,’s2’)
string 希望被替換的字符或變量
s1 被替換的字符串
s2 要替換的字符串
SQL> select replace(‘he love you’,’he’,’i’) from dual;

REPLACE(‘H

i love you

13.SOUNDEX
返回一個與給定的字符串讀音相同的字符串
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 剪掉前面的字符
TRAILING 剪掉後面的字符
如果不指定,默認爲空格符
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
返回一個數字的反正切值
SQL> select atan(1) from dual;

ATAN(1)

.78539816

19.CEIL
返回大於或等於給出數字的最小整數
SQL> select ceil(3.1415927) from dual;

CEIL(3.1415927)

          4

20.COS
返回一個給定數字的餘弦
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
返回一個數字的對數值
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爲底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
返回一個數字的正弦值
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
返回數字的正切值
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.mm.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
將字符數據類型轉換爲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)
將源字符串 sset從一個語言字符集轉換到另一個目的dset字符集
SQL> select convert(‘strutz’,’we8hp’,’f7dec’) “conversion” from dual;

conver

strutz

44.HEXTORAW
將一個十六進制構成的字符串轉換爲二進制

45.RAWTOHEXT
將一個二進制構成的字符串轉換爲十六進制

46.ROWIDTOCHAR
將ROWID數據類型轉換爲字符類型

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’)
將字符串轉化爲ORACLE中的一個日期

49.TO_MULTI_BYTE
將字符串中的單字節字符轉化爲多字節字符
SQL> select to_multi_byte(‘高’) from dual;

TO

高

50.TO_NUMBER
將給出的字符轉換爲數字
SQL> select to_number(‘1999’) year from dual;

YEAR

 1999

51.BFILENAME(dir,file)
指定一個外部二進制文件
SQL>insert into file_tb1 values(bfilename(‘lob_dir1’,’image1.gif’));

52.CONVERT(‘x’,’desc’,’source’)
將x字段或變量的源source轉換爲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數據類型字段進行初始化操作的函數

55.GREATEST
返回一組表達式中的最大值,即比較字符的編碼大小.
SQL> select greatest(‘AA’,’AB’,’AC’) from dual;

GR

AC
SQL> select greatest(‘啊’,’安’,’天’) from dual;

GR

天

56.LEAST
返回一組表達式中的最小值
SQL> select least(‘啊’,’安’,’天’) from dual;

LE

啊

57.UID
返回標識當前用戶的唯一整數
SQL> show user
USER 爲”GAO”
SQL> select username,user_id from dba_users where user_id=uid;
USERNAME USER_ID

---

GAO 25

58.USER
返回當前用戶的名字
SQL> select user from dual;

USER

GAO

59.USEREVN
返回當前用戶環境的信息,opt可以是:
ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZE
ISDBA 查看當前用戶是否是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
返回當前環境變量
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
返回用戶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(字節)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)
求協方差
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 count()>=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 deptno ;
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