oracle函数大全

liugmwx 发表于 2007-11-8 21:52:28

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('***ith') upp from dual;
UPP ----- ***ith
 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1 J 出现的位置,默认为1 SQL> 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 gao.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RTRIM LTRIM 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('H ---------- 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 -------- weather wether
 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) --------- --------- 0 2
 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 ------ 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 2004.05.10 SQL> 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 ----------- 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') 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_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') 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 ***ITH AAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLEN AAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARD AAAAfKAACAAAAEqAAD 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 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() 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 -- AC SQL> 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 user USER 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,VSIZE ISDBA 查看当前用户是否是DBA如果是则返回true SQL> select userenv('isdba') from dual;
USEREN ------ FALSE SQL> select userenv('isdba') from dual;
USEREN ------ TRUE SESSION 返回会话标志 SQL> select userenv('sessionid') from dual;
USERENV('SESSIONID') -------------------- 152 ENTRYID 返回会话人口标志 SQL> select userenv('entryid') from dual;
USERENV('ENTRYID') ------------------ 0 INSTANCE 返回当前INSTANCE的标志 SQL> select userenv('instance') from dual;
USERENV('INSTANCE') ------------------- 1 LANGUAGE 返回当前环境变量 SQL> select userenv('language') from dual;
USERENV('LANGUAGE') ---------------------------------------------------- SIMPLIFIED CHINESE_CHINA.ZHS16GBK LANG 返回当前环境的语言的缩写 SQL> select userenv('lang') from dual;
USERENV('LANG') ---------------------------------------------------- ZHS TERMINAL 返回用户的终端或机器的标志 SQL> select userenv('terminal') from dual;
USERENV('TERMINA ---------------- GAO VSIZE(X) 返回X的大小(字节)数 SQL> select vsize(user),user from dual;
VSIZE(USER) USER ----------- ------------------------------ 6 SYSTEM

60.***G(DISTINCT|ALL) all表示对所有的值求平均值,distinct只对不同的值求平均值 SQLWKS> create table table3(xm varchar(8),sal number(7,2)); 语句已处理。 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 ***g(distinct sal) from gao.table3;
***G(DISTINCTSAL) ---------------- 3333.33
SQL> select ***g(all sal) from gao.table3;
***G(ALLSAL) ----------- 2592.59
 61.MAX(DISTINCT|ALL) 求最大值,ALL表示对所有的值求最大值,DISTINCT表示对不同的值求最大值,嗤闹蝗∫淮?br />SQL> select max(distinct sal) from scott.emp;
MAX(DISTINCTSAL) ---------------- 5000
 62.MIN(DISTINCT|ALL) 求最小值,ALL表示对所有的值求最小值,DISTINCT表示对不同的值求最小值,相同的只取一次 SQL> select min(all sal) from gao.table3;
MIN(ALLSAL) ----------- 1111.11
 63.STDDEV(distinct|all) 求标准差,ALL表示对所有的值求标准差,DISTINCT表示只对不同的值求标准差 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) 求协方差 
SQL> select variance(sal) from scott.emp;
VARIANCE(SAL) ------------- 1398313.9
 65.GROUP BY 主要用来对一组数进行统计 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.H***ING 对分组统计再加限制条件 SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno h***ing count(*)>=5;
DEPTNO COUNT(*) SUM(SAL) --------- --------- --------- 20 5 10875 30 6 9400 SQL> select deptno,count(*),sum(sal) from scott.emp h***ing count(*)>=5 group by deptno ;
DEPTNO COUNT(*) SUM(SAL) --------- --------- --------- 20 5 10875 30 6 9400
 67.ORDER BY 用于对查询到的结果进行排序输出 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 ***ITH 800 30 *** 2850 30 ALLEN 1600 30 TURNER 1500 30 WARD 1250 30 MARTIN 1250 30 JAMES 950

页: [1]

栖息谷-管理人的网上家园's Archiver

oracle函数大全