ORACLE常用函數

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 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

                                       ORACLE常用函數（一）
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        322.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 A3.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234.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-----Smith5.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1J     出現的位置,預設為1SQL> select instr('oracle traning','ra',1,2) instring from dual; INSTRING---------        96.LENGTH返回字串的長度;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返回字串,並將所有的字元小寫SQL> select lower('AaBbCcDd')AaBbCcDd from dual;AABBCCDD--------aabbccdd8.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RTRIMLTRIM  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 jing11.SUBSTR(string,start,count)取子字串,從start開始,取count個SQL> select substr('13088888888',3,8) from dual;SUBSTR('--------0888888812.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('H----------i love you13.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--------weatherwether14.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       10016.ACOS給出反餘弦的值SQL> select acos(-1) from dual; ACOS(-1)---------3.141592717.ASIN給出反正弦的值SQL> select asin(0.5) from dual;ASIN(0.5)---------.5235987818.ATAN返回一個數位反正切值SQL> select atan(1) from dual;  ATAN(1)---------.7853981619.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)---------------              420.COS返回一個給定數位餘弦SQL> select cos(-3.1415927) from dual;COS(-3.1415927)---------------             -121.COSH返回一個數字反餘弦值SQL> select cosh(20) from dual; COSH(20)---------24258259822.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 2.718281823.FLOOR對給定的數字取整數SQL> select floor(2345.67) from dual;FLOOR(2345.67)--------------          234524.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     .9999999925.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         226.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         227.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         2728.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          -5529.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0SQL> select sign(123),sign(-100),sign(0) from dual;SIGN(123) SIGN(-100)   SIGN(0)--------- ---------- ---------        1         -1         030.SIN返回一個數位正弦值SQL> select sin(1.57079) from dual;SIN(1.57079)------------           131.SIGH返回雙曲正弦的值SQL> select sin(20),sinh(20) from dual;  SIN(20)  SINH(20)--------- ---------.91294525 24258259832.SQRT返回數字n的根SQL> select sqrt(64),sqrt(10) from dual; SQRT(64)  SQRT(10)--------- ---------        8 3.162277733.TAN返回數位正切值SQL> select tan(20),tan(10) from dual;  TAN(20)   TAN(10)--------- ---------2.2371609 .6483608334.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------200002SQL> select to_char(add_months(to_date('199912','yyyymm'),-2),'yyyymm') from dual;TO_CHA------19991037.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 2004.05.10SQL> select last_day(sysdate) from dual;LAST_DAY(S----------31-5月 -0438.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-----------          9SQL>selectmonths_between(to_date('2000.05.20','yyyy.mm.dd'),to_date('2005.05.20','yyyy.mm.dd')) mon_betw from dual; MON_BETW---------      -6039.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 18:05:3240.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 SMITHAAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLENAAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARDAAAAfKAACAAAAEqAAD AAAAfKAACAAAAEqAAD JONES43.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------strutz44.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---------     199951.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                                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
        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1J     出現的位置,預設為1SQL> 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 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RTRIMLTRIM  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('H----------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--------weatherwether
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0SQL> 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------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 2004.05.10SQL> 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-----------          9SQL>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 SMITHAAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLENAAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARDAAAAfKAACAAAAEqAAD 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                                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