oracle函数大全

目 录目 录1查看回滚段名称及大小3ASCII3CHR3CONCAT4INITCAP4INSTR(C1,C2,I,J)4LENGTH4LOWER5UPPER5RPAD和LPAD(粘贴字符)5LTRIM和RTRIM5SUBSTR(string,start,count)6REPLACE(string,s1,s2)6SOUNDEX6TRIM(s from string)7ABS7ACOS7ASIN7ATAN7CEIL8COS8COSH8EXP8FLOOR8LN9LOG(n1,n2)9MOD(n1,n2)9POWER9ROUND和TRUNC10SIGN10SIN10SIGH10SQRT10TAN11TANH11TRUNC11ADD_MONTHS11LAST_DAY12MONTHS_BETWEEN(date2,date1)12NEW_TIME(date,this,that)12NEXT_DAY(date,day)13SYSDATE13CHARTOROWID13CONVERT(c,dset,sset)14HEXTORAW14RAWTOHEXT14ROWIDTOCHAR14TO_CHAR(date,format)14TO_DATE(string,format)14TO_MULTI_BYTE15TO_NUMBER15BFILENAME(dir,file)15CONVERT(x,desc,source)15DUMP(s,fmt,start,length)16EMPTY_BLOB()和EMPTY_CLOB()16GREATEST16LEAST17UID17USER17USEREVN17AVG(DISTINCT|ALL)19MAX(DISTINCT|ALL)19MIN(DISTINCT|ALL)20STDDEV(distinct|all)20VARIANCE(DISTINCT|ALL)20GROUP BY20HAVING21ORDER BY21 查看回滚段名称及大小select segment_name, tablespace_name, r.status, (initial_extent/1024) InitialExtent,(next_extent/1024) NextExtent, max_extents, v.curext CurExtentFrom dba_rollback_segs r, v$rollstat vWhere r.segment_id = v.usn(+)order by segment_name;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 32CHR给出整数,返回对应的字符;SQL select chr(54740) zhao,chr(65) chr65 from dual;ZH C- -赵 ACONCAT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23INITCAP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-SmithINSTR(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-9LENGTH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 7LOWER返回字符串,并将所有的字符小写SQL select lower(AaBbCcDd)AaBbCcDd from dual;AABBCCDD-aabbccddUPPER返回字符串,并将所有的字符大写SQL select upper(AaBbCcDd) upper from dual;UPPER-AABBCCDDRPAD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 jingSUBSTR(string,start,count)取子字符串,从start开始,取count个SQL select substr(13088888888,3,8) from dual;SUBSTR(-08888888REPLACE(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 youSOUNDEX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-weatherwetherTRIM(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 ABS返回指定值的绝对值SQL select abs(100),abs(-100) from dual;ABS(100) ABS(-100)- -100 100ACOS给出反余弦的值SQL select acos(-1) from dual;ACOS(-1)-3.1415927ASIN给出反正弦的值SQL select asin(0.5) from dual;ASIN(0.5)-.52359878ATAN返回一个数字的反正切值SQL select atan(1) from dual;ATAN(1)-.78539816CEIL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)-4COS返回一个给定数字的余弦SQL select cos(-3.1415927) from dual;COS(-3.1415927)-1COSH返回一个数字反余弦值SQL select cosh(20) from dual;COSH(20)-242582598EXP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 2.7182818FLOOR对给定的数字取整数SQL select floor(2345.67) from dual;FLOOR(2345.67)-2345LN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 .99999999LOG(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 2MOD(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 2POWER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 27ROUND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 -55SIGN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 0SIN返回一个数字的正弦值SQL select sin(1.57079) from dual;SIN(1.57079)-1SIGH返回双曲正弦的值SQL select sin(20),sinh(20) from dual;SIN(20) SINH(20)- -.91294525 242582598SQRT返回数字n的根SQL select sqrt(64),sqrt(10) from dual;SQRT(64) SQRT(10)- -8 3.1622777TAN返回数字的正切值SQL select tan(20),tan(10) from dual;TAN(20) TAN(10)- -2.2371609 .64836083TANH返回数字n的双曲正切值SQL select tanh(20),tan(20) from dual;TANH(20) TAN(20)- -1 2.2371609TRUNC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)- -100 124.16ADD_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-199910LAST_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 -04MONTHS_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-9SQLselectmonths_between(to_date(2000.05.20,yyyy.mm.dd),to_date(2005.05.20,yyyy.mm.dd) mon_betw from dual;MON_BETW-60NEW_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 18:05:32NEXT_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 -01SYSDATE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 11:17:00CHARTOROWID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 JONESCONVERT(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-strutzHEXTORAW将一个十六进制构成的字符串转换为二进制RAWTOHEXT将一个二进制构成的字符串转换为十六进制ROWIDTOCHAR将ROWID数据类型转换为字符类型TO_CHAR(date,format)SQL select to_char(sysdate,yyyy/mm/dd hh24:mi:ss) from dual;TO_CHAR(SYSDATE,YY-2004/05/09 21:14:41TO_DATE(string,format)将字符串转化为ORACLE中的一个日期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TO_NUMBER将给出的字符转换为数字SQL select to_number(1999) year from dual;YEAR-1999BFILENAME(dir,file)指定一个外部二进制文件SQLinsert into file_tb1 values(bfilename(lob_dir1,image1.gif);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 noneDUMP(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,DEMPTY_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LEAST返回一组表达式中的最小值 SQL select least(啊,安,天) from dual;LE-啊UID返回标识当前用户的唯一整数SQL show userUSER 为GAOSQL select username,user_id from dba_users where user_id=uid;USERNAME USER_ID- -GAO 25USER返回当前用户的名字SQL select user from dual;USER-GAOUSEREVN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 SYSTEMAVG(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 avg(distinct sal) from gao.table3;AVG(DISTINCTSAL)-3333.33SQL select avg(all sal) from gao.table3;AVG(ALLSAL)-2592.59MAX(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,相同的只取一次SQL select max(distinct sal) from scott.emp;MAX(DISTINCTSAL)-5000MIN(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)-1111.11STDDEV(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)-1182.5032SQL select stddev(distinct sal) from scott.emp;STDDEV(DISTINCTSAL)-1229.951VARIANCE(DISTINCT|ALL)求协方差 SQL select variance(sal) from scott.emp;VARIANCE(SAL)-1398313.9GROUP 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 875020 5 1087530 6 9400HAVING对分组统计再加限制条件SQL select deptno,count(*),sum(sal) from scott.emp group by deptno having count(*)=5;DEPTNO COUNT(*) SUM(SAL)- - -20 5 1087530 6 9400SQL select deptno,count(*),sum(sal) from scott.emp having count(*)=5 group by deptno ;DEPTNO COUNT(*) SUM(SAL)- - -20 5 1087530 6 9400ORDER 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 500010 CLARK 245010 MILLER 130020 SCOTT 300020 FORD 300020 JONES 297520 ADAMS 110020 SMITH 80030 BLAKE 285030 ALLEN 160030 TURNER 150030 WARD 125030 MARTIN 125030 JAMES 950