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
ORACLE常用函数（一）
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 48 322.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 A3.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234.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-----Smith5.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--------- 96.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--------aabbccdd8.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 jing11.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('--------0888888812.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 you13.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--------weatherwether14.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 10016.ACOS给出反余弦的值SQL> select acos(-1) from dual; ACOS(-1)---------3.141592717.ASIN给出反正弦的值SQL> select asin(0.5) from dual;ASIN(0.5)---------.5235987818.ATAN返回一个数字的反正切值SQL> select atan(1) from dual; ATAN(1)---------.7853981619.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)--------------- 420.COS返回一个给定数字的余弦SQL> select cos(-3.1415927) from dual;COS(-3.1415927)--------------- -121.COSH返回一个数字反余弦值SQL> select cosh(20) from dual; COSH(20)---------24258259822.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 2.718281823.FLOOR对给定的数字取整数SQL> select floor(2345.67) from dual;FLOOR(2345.67)-------------- 234524.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 .9999999925.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)--------- --------- 0 226.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 0 227.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 -5529.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 -1 030.SIN返回一个数字的正弦值SQL> select sin(1.57079) from dual;SIN(1.57079)------------ 131.SIGH返回双曲正弦的值SQL> select sin(20),sinh(20) from dual; SIN(20) SINH(20)--------- ---------.91294525 24258259832.SQRT返回数字n的根SQL> select sqrt(64),sqrt(10) from dual; SQRT(64) SQRT(10)--------- --------- 8 3.162277733.TAN返回数字的正切值SQL> select tan(20),tan(10) from dual; TAN(20) TAN(10)--------- ---------2.2371609 .6483608334.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------19991037.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 -0438.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.mm.dd')) mon_betw from dual; MON_BETW--------- -6039.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 18:05:3240.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 JONES43.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------strutz44.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--------- 199951.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 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 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('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--------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)--------- --------- 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.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 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 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