Oracle SQL 内置函数大全(转)

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Oracle SQL 内置函数大全(转)

2024-07-01 03:50| 来源: 网络整理| 查看: 265

SQL中的单记录函数

1.ASCII 返回与指定的字符对应的十进制数;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 给出整数,返回对应的字符;SQL> select chr(54740) zhao,chr(65) chr65 from dual;

ZH C-- -赵 A

3.CONCAT 连接两个字符串;SQL> select concat('010-','88888888')||'转23' 高乾竞电话 from dual;

高乾竞电话----------------010-88888888转23

4.INITCAP 返回字符串并将字符串的第一个字母变为大写;SQL> select initcap('smith') upp from dual;

UPP-----Smith

5.INSTR(C1,C2,I,J) 在一个字符串中搜索指定的字符,返回发现指定的字符的位置;C1 被搜索的字符串C2 希望搜索的字符串I 搜索的开始位置,默认为1J 出现的位置,默认为1SQL> select instr('oracle traning','ra',1,2) instring from dual;

INSTRING---------9

6.LENGTH 返回字符串的长度;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))------ ------------ ---------------- ------------ --------- --------------------高乾竞 3 北京市海锭区 6 9999.99 7

7.LOWER 返回字符串,并将所有的字符小写SQL> select lower('AaBbCcDd')AaBbCcDd from dual;

AABBCCDD--------aabbccdd

8.UPPER 返回字符串,并将所有的字符大写SQL> select upper('AaBbCcDd') upper from dual;

UPPER--------AABBCCDD

9.RPAD和LPAD(粘贴字符)RPAD 在列的右边粘贴字符LPAD 在列的左边粘贴字符SQL> select lpad(rpad('gao',10,'*'),17,'*')from dual;

LPAD(RPAD('GAO',1-----------------*******gao*******不够字符则用*来填满

10.LTRIM和RTRIMLTRIM 删除左边出现的字符串RTRIM 删除右边出现的字符串SQL> select ltrim(rtrim(' gao qian jing ',' '),' ') from dual;

LTRIM(RTRIM('-------------gao qian jing

11.SUBSTR(string,start,count)取子字符串,从start开始,取count个SQL> select substr('13088888888',3,8) from dual;

SUBSTR('--------08888888

12.REPLACE('string','s1','s2')string 希望被替换的字符或变量s1 被替换的字符串s2 要替换的字符串SQL> select replace('he love you','he','i') from dual;

REPLACE('HELOVEYOU','HE','I')------------------------------i love you

13.SOUNDEX 返回一个与给定的字符串读音相同的字符串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--------weatherwether

14.TRIM('s' from 'string')LEADING 剪掉前面的字符TRAILING 剪掉后面的字符如果不指定,默认为空格符

15.ABS 返回指定值的绝对值SQL> select abs(100),abs(-100) from dual;

ABS(100) ABS(-100)--------- ---------100 100

16.ACOS 给出反余弦的值SQL> select acos(-1) from dual;

ACOS(-1)---------3.1415927

17.ASIN 给出反正弦的值SQL> select asin(0.5) from dual;

ASIN(0.5)---------.52359878

18.ATAN 返回一个数字的反正切值SQL> select atan(1) from dual;

ATAN(1)---------.78539816

19.CEIL 返回大于或等于给出数字的最小整数SQL> select ceil(3.1415927) from dual;

CEIL(3.1415927)---------------4

20.COS 返回一个给定数字的余弦SQL> select cos(-3.1415927) from dual;

COS(-3.1415927)----------------1

21.COSH 返回一个数字反余弦值SQL> select cosh(20) from dual;

COSH(20)---------242582598

22.EXP 返回一个数字e的n次方根SQL> select exp(2),exp(1) from dual;

EXP(2) EXP(1)--------- ---------7.3890561 2.7182818

23.FLOOR 对给定的数字取整数SQL> select floor(2345.67) from dual;

FLOOR(2345.67)--------------2345

24.LN 返回一个数字的对数值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) 返回一个以n1为底n2的对数SQL> select log(2,1),log(2,4) from dual;

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

26.MOD(n1,n2) 返回一个n1除以n2的余数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按照指定的精度进行舍入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 取数字n的符号,大于0返回1,小于0返回-1,等于0返回0SQL> select sign(123),sign(-100),sign(0) from dual;

SIGN(123) SIGN(-100) SIGN(0)--------- ---------- ---------1 -1 0

30.SIN 返回一个数字的正弦值SQL> select sin(1.57079) from dual;

SIN(1.57079)------------1

31.SIGH 返回双曲正弦的值SQL> select sin(20),sinh(20) from dual;

SIN(20) SINH(20)--------- ---------.91294525 242582598

32.SQRT 返回数字n的根SQL> select sqrt(64),sqrt(10) from dual;

SQRT(64) SQRT(10)--------- ---------8 3.1622777

33.TAN 返回数字的正切值SQL> select tan(20),tan(10) from dual;

TAN(20) TAN(10)--------- ---------2.2371609 .64836083

34.TANH返回数字n的双曲正切值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个数SQL> select trunc(124.1666,-2) trunc1,trunc(124.16666,2) from dual;

TRUNC1 TRUNC(124.16666,2)--------- ------------------100 124.16

36.ADD_MONTHS增加或减去月份SQL> select to_char(add_months(to_date('199912','yyyymm'),2),'yyyymm') from dual;

TO_CHA------200002SQL> select to_char(add_months(to_date('199912','yyyymm'),-2),'yyyymm') from dual;

TO_CHA------199910

37.LAST_DAY返回日期的最后一天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 2004.05.10SQL> select last_day(sysdate) from dual;

LAST_DAY(S----------31-5月 -04

38.MONTHS_BETWEEN(date2,date1)给出date2-date1的月份SQL> select months_between('19-12月-1999','19-3月-1999') mon_between from dual;

MON_BETWEEN-----------9SQL>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')给出在this时区=other时区的日期和时间SQL> select to_char(sysdate,'yyyy.mm.dd hh24:mi:ss') bj_time,to_char(new_time2 (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')给出日期date和星期x之后计算下一个星期的日期SQL> select next_day('18-5月-2001','星期五') next_day from dual;

NEXT_DAY----------25-5月 -01

41.SYSDATE 用来得到系统的当前日期SQL> select to_char(sysdate,'dd-mm-yyyy day') from dual;

TO_CHAR(SYSDATE,'-----------------09-05-2004 星期日trunc(date,fmt)按照给出的要求将日期截断,如果fmt='mi'表示保留分,截断秒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 将字符数据类型转换为ROWID类型SQL> select rowid,rowidtochar(rowid),ename from scott.emp;

ROWID ROWIDTOCHAR(ROWID) ENAME------------------ ------------------ ----------AAAAfKAACAAAAEqAAA AAAAfKAACAAAAEqAAA SMITHAAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLENAAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARDAAAAfKAACAAAAEqAAD AAAAfKAACAAAAEqAAD JONES

43.CONVERT(c,dset,sset)将源字符串 sset从一个语言字符集转换到另一个目的dset字符集SQL> select convert('strutz','we8hp','f7dec') "conversion" from dual;

conver------strutz

44.HEXTORAW 将一个十六进制构成的字符串转换为二进制

45.RAWTOHEXT 将一个二进制构成的字符串转换为十六进制

46.ROWIDTOCHAR 将ROWID数据类型转换为字符类型

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') 将字符串转化为ORACLE中的一个日期

49.TO_MULTI_BYTE 将字符串中的单字节字符转化为多字节字符SQL> select to_multi_byte('高') from dual;

TO--高

50.TO_NUMBER将给出的字符转换为数字SQL> select to_number('1999') year from dual;

YEAR---------1999

51.BFILENAME(dir,file)指定一个外部二进制文件SQL>insert into file_tb1 values(bfilename('lob_dir1','image1.gif'));

52.CONVERT('x','desc','source') 将x字段或变量的源source转换为descSQL> 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 none2 1 none3 1 none4 1 none5 1 none6 1 none7 1275 none8 1275 none9 20 GAO select10 40 GAO none

53.DUMP(s,fmt,start,length)DUMP函数以fmt指定的内部数字格式返回一个VARCHAR2类型的值SQL> col global_name for a30SQL> col dump_string for a50SQL> set lin 200SQL> 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()这两个函数都是用来对大数据类型字段进行初始化操作的函数

55.GREATEST返回一组表达式中的最大值,即比较字符的编码大小.SQL> select greatest('AA','AB','AC') from dual;

GR--ACSQL> select greatest('啊','安','天') from dual;

GR--天

56.LEAST返回一组表达式中的最小值SQL> select least('啊','安','天') from dual;

LE--啊

57.UID返回标识当前用户的唯一整数SQL> show userUSER 为"GAO"SQL> select username,user_id from dba_users where user_id=uid;

USERNAME USER_ID------------------------------ ---------GAO 25

58.USER返回当前用户的名字SQL> select user from dual;

USER------------------------------GAO

59.USEREVN返回当前用户环境的信息,opt可以是:ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZEISDBA 查看当前用户是否是DBA如果是则返回trueSQL> select userenv('isdba') from dual;

USEREN------FALSESQL> select userenv('isdba') from dual;

USEREN------TRUESESSION返回会话标志SQL> select userenv('sessionid') from dual;

USERENV('SESSIONID')--------------------152ENTRYID返回会话人口标志SQL> select userenv('entryid') from dual;

USERENV('ENTRYID')------------------0INSTANCE返回当前INSTANCE的标志SQL> select userenv('instance') from dual;

USERENV('INSTANCE')-------------------1LANGUAGE返回当前环境变量SQL> select userenv('language') from dual;

USERENV('LANGUAGE')----------------------------------------------------SIMPLIFIED CHINESE_CHINA.ZHS16GBKLANG返回当前环境的语言的缩写SQL> select userenv('lang') from dual;

USERENV('LANG')----------------------------------------------------ZHSTERMINAL返回用户的终端或机器的标志SQL> select userenv('terminal') from dual;

USERENV('TERMINA----------------GAOVSIZE(X)返回X的大小(字节)数SQL> select vsize(user),user from dual;

VSIZE(USER) USER----------- ------------------------------6 SYSTEM