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SQL中的單記錄函數(shù)有哪些
1.ASCII
返回與指定的字符對(duì)應(yīng)的十進(jìn)制數(shù);
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(shù),返回對(duì)應(yīng)的字符;
SQL> select chr(54740) zhao,chr(65) chr65 from dual;
ZH C
趙 A
3.CONCAT
連接兩個(gè)字符串;
SQL> select concat('010-','88888888')'轉(zhuǎn)23'; 高乾競(jìng)電話 from dual;
高乾競(jìng)電話
010-88888888轉(zhuǎn)23
4.INITCAP
返回字符串并將字符串的第一個(gè)字母變?yōu)榇髮?
SQL> select initcap('smith') upp from dual;
UPP
Smith
5.INSTR(C1,C2,I,J)
在一個(gè)字符串中搜索指定的字符,返回發(fā)現(xiàn)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;;搜索的開始位置,默認(rèn)為1
J;;出現(xiàn)的位置,默認(rèn)為1
SQL> select instr('Oracle traning','ra',1,2) instring from dual;
;INSTRING
;;;;;9
6.LENGTH
返回字符串的長(zhǎng)度;
SQL> select name,length(name),addr,length(addr),sal,length(to_sal)) from gao.nchar_tst;
NAMELENGTH(NAME) ADDR;;LENGTH(ADDR);;;;SAL LENGTH(TO_CHAR(SAL))
高乾競(jìng);3 北京市海錠區(qū);;;;;69999.99;7
7.LOWER
返回字符串,并將所有的字符小寫
SQL> select lower('AaBbCcDd')AaBbCcDd from dual;
AABBCCDD
aabbccdd
8.UPPER
返回字符串,并將所有的字符大寫
SQL> select upper('AaBbCcDd') upper from dual;
UPPER
AABBCCDD
9.RPAD和LPAD(粘貼字符)
RPAD; 在列的右邊粘貼字符
LPAD; 在列的左邊粘貼字符
SQL> select lpad(rpad('gao',10,'*'),17,'*')from dual;
LPAD(RPAD('GAO',1
*******gao*******
不夠字符則用*來填滿
10.LTRIM和RTRIM
LTRIM; 刪除左邊出現(xiàn)的字符串
RTRIM; 刪除右邊出現(xiàn)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,從start開始,取count個(gè)
SQL> select substr('13088888888',3,8) from dual;
SUBSTR('
08888888
12.REPLACE('string','s1','s2')
string希望被替換的字符或變量
s1;;;;被替換的字符串
s2;;;;要替換的字符串
SQL> select replace('he love you','he','i') from dual;
REPLACE('H
i love you
13.SOUNDEX
返回一個(gè)與給定的字符串讀音相同的字符串
SQL> create table table1(xm var8));
SQL> into table1 values('weather');
SQL> into table1 values('wether');
SQL> 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
假如不指定,默認(rèn)為空格符
15.ABS
返回指定值的絕對(duì)值
SQL> select abs(100),abs(-100) from dual;
;ABS(100) ABS(-100)
;;;100;;;;100
16.ACOS
給出反余弦的值
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(gè)數(shù)字的反正切值
SQL> select atan(1) from dual;
; ATAN(1)
.78539816
19.CEIL
返回大于或等于給出數(shù)字的最小整數(shù)
SQL> select ceil(3.1415927) from dual;
CEIL(3.1415927)
;;;4
20.COS
返回一個(gè)給定數(shù)字的余弦
SQL> select cos(-3.1415927) from dual;
COS(-3.1415927)
;;-1
21.COSH
返回一個(gè)數(shù)字反余弦值
SQL> select cosh(20) from dual;
;COSH(20)
242582598
22.EXP
返回一個(gè)數(shù)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(duì)給定的數(shù)字取整數(shù)
SQL> select floor(2345.67) from dual;
FLOOR(2345.67)
; 2345
24.LN
返回一個(gè)數(shù)字的對(duì)數(shù)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(gè)以n1為底n2的對(duì)數(shù)
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(gè)n1除以n2的余數(shù)
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(jìn)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(shù)字n的符號(hào),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
返回一個(gè)數(shù)字的正弦值
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?cái)?shù)字n的根
SQL> select sqrt(64),sqrt(10) from dual;
;SQRT(64); SQRT(10)
;;;;;8 3.1622777
33.TAN
返回?cái)?shù)字的正切值
SQL> select tan(20),tan(10) from dual;
; TAN(20)TAN(10)
2.2371609 .64836083
34.TANH
返回?cái)?shù)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(gè)數(shù)
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_add_months(to_date('199912','yyyymm'),2),'yyyymm') from dual;
TO_CHA
200002
SQL> select to_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_sysdate,'yyyy.mm.dd'),to_(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)
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
; 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')
給出在this時(shí)區(qū)=other時(shí)區(qū)的日期和時(shí)間
SQL> select to_sysdate,'yyyy.mm.dd hh24:mi:ss') bj_time,to_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之后計(jì)算下一個(gè)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(tǒng)的當(dāng)前日期
SQL> select to_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?cái)?假如fmt='mi'表示保留分,截?cái)嗝?/p>
SQL> select to_trunc(sysdate,'hh'),'yyyy.mm.dd hh24:mi:ss') hh,
; 2; to_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
將字符數(shù)據(jù)類型轉(zhuǎn)換為ROWID類型
SQL> select rowid,rowidtorowid),ename from scott.emp;
ROWID;;;ROWIDTOCHAR(ROWID) ENAME
AAAAfKAACAAAAEqAAA AAAAfKAACAAAAEqAAA SMITH
AAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLEN
AAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARD
AAAAfKAACAAAAEqAAD AAAAfKAACAAAAEqAAD JONES
43.CONVERT(c,dset,sset)
將源字符串 sset從一個(gè)語言字符集轉(zhuǎn)換到另一個(gè)目的dset字符集
SQL> select convert('strutz','we8hp','f7dec') "conversion" from dual;
conver
strutz
44.HEXTORAW
將一個(gè)十六進(jìn)制構(gòu)成的字符串轉(zhuǎn)換為二進(jìn)制
45.RAWTOHEXT
將一個(gè)二進(jìn)制構(gòu)成的字符串轉(zhuǎn)換為十六進(jìn)制
46.ROWIDTOCHAR
將ROWID數(shù)據(jù)類型轉(zhuǎn)換為字符類型
47.TO_CHAR(date,'format')
SQL> select to_sysdate,'yyyy/mm/dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
2004/05/09 21:14:41
48.TO_DATE(string,'format')
將字符串轉(zhuǎn)化為ORACLE中的一個(gè)日期
49.TO_MULTI_BYTE
將字符串中的單字節(jié)字符轉(zhuǎn)化為多字節(jié)字符
SQL>select to_multi_byte('高') from dual;
TO
高
50.TO_NUMBER
將給出的字符轉(zhuǎn)換為數(shù)字
SQL> select to_number('1999') year from dual;
;;YEAR
;;1999
51.BFILENAME(dir,file)
指定一個(gè)外部二進(jìn)制文件
SQL> into file_tb1 values(bfilename('lob_dir1','image1.gif'));
52.CONVERT('x','desc','source')
將x字段或變量的源source轉(zhuǎn)換為desc
SQL> select sid,serial#,username,decode(command,
; 2; 0,'none',
; 3; 2,'',
; 4; 3,
; 5; 'select',
; 6; 6,'update',
; 7; 7,'',
; 8; 8,'drop',
; 9; 'other') cmd; from v$session where type!='background';
;;;SIDSERIAL# 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函數(shù)以fmt指定的內(nèi)部數(shù)字格式返回一個(gè)VARCHAR2類型的值
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.WORLDTyp=1 Len=12 CharacterSet=ZHS16GBK: W,O,R,L,D
54.EMPTY_BLOB()和EMPTY_CLOB()
這兩個(gè)函數(shù)都是用來對(duì)大數(shù)據(jù)類型字段進(jìn)行初始化操作的函數(shù)
55.GREATEST
返回一組表達(dá)式中的最大值,即比較字符的編碼大小.
SQL> select greatest('AA','AB','AC') from dual;
GR
AC
SQL> select greatest('啊','安','天') from dual;
GR
天
56.LEAST
返回一組表達(dá)式中的最小值
SQL> select least('啊','安','天') from dual;
LE
啊
57.UID
返回標(biāo)識(shí)當(dāng)前用戶的唯一整數(shù)
SQL> show user
USER 為"GAO"
SQL> select username,user_id from dba_users where user_id=uid;
USERNAME USER_ID
GAO25
58.USER
返回當(dāng)前用戶的名字
SQL> select user from; dual;
USER
GAO
59.USEREVN
返回當(dāng)前用戶環(huán)境的信息,opt可以是:
ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZE
ISDBA; 查看當(dāng)前用戶是否是DBA假如是則返回true
SQL> select userenv('isdba') from dual;
USEREN
FALSE
SQL> select userenv('isdba') from dual;
USEREN
TRUE
SESSION
返回會(huì)話標(biāo)志
SQL> select userenv('sessionid') from dual;
USERENV('SESSIONID')
152
ENTRYID
返回會(huì)話人口標(biāo)志
SQL> select userenv('entryid') from dual;
USERENV('ENTRYID')
INSTANCE
返回當(dāng)前INSTANCE的標(biāo)志
SQL> select userenv('instance') from dual;
USERENV('INSTANCE')
; 1
LANGUAGE
返回當(dāng)前環(huán)境變量
SQL> select userenv('language') from dual;
USERENV('LANGUAGE')
SIMPLIFIED CHINESE_CHINA.ZHS16GBK
LANG
返回當(dāng)前環(huán)境的語言的縮寫
SQL> select userenv('lang') from dual;
USERENV('LANG')
ZHS
TERMINAL
返回用戶的終端或機(jī)器的標(biāo)志
SQL> select userenv('terminal') from dual;
USERENV('TERMINA
GAO
VSIZE(X)
返回X的大小(字節(jié))數(shù)
SQL> select vsize(user),user from dual;
VSIZE(USER) USER
; 6 SYSTEM
60.AVG(DISTINCTALL)
all表示對(duì)所有的值求平均值,distinct只對(duì)不同的值求平均值
SQLWKS> create table table3(xm var8),sal number(7,2));
語句已處理。
SQLWKS> into table3 values('gao',1111.11);
SQLWKS> into table3 values('gao',1111.11);
SQLWKS> into table3 values('zhu',5555.55);
SQLWKS> commit;
SQL> select avg(distinct sal) from gao.table3;
AVG(DISTINCTSAL)
3333.33
SQL> select avg(all sal) from gao.table3;
AVG(ALLSAL)
;2592.59
61.MAX(DISTINCTALL)
求最大值,ALL表示對(duì)所有的值求最大值,DISTINCT表示對(duì)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)
;5000
62.MIN(DISTINCTALL)
求最小值,ALL表示對(duì)所有的值求最小值,DISTINCT表示對(duì)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(distinctall)
求標(biāo)準(zhǔn)差,ALL表示對(duì)所有的值求標(biāo)準(zhǔn)差,DISTINCT表示只對(duì)不同的值求標(biāo)準(zhǔn)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(DISTINCTALL)
求協(xié)方差
SQL> select variance(sal) from scott.emp;
VARIANCE(SAL)
;1398313.9
65.GROUP BY
主要用來對(duì)一組數(shù)進(jìn)行統(tǒng)計(jì)
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.HAVING
對(duì)分組統(tǒng)計(jì)再加限制條件
SQL> select deptno,count(*),sum(sal) from scott.emp group by deptno having count(*)>=5;
DEPTNO; COUNT(*); SUM(SAL)
;;;;20 5;;10875
;;;;30 6;;;9400
SQL> select deptno,count(*),sum(sal) from scott.emp having count(*)>=5 group by deptno ;
DEPTNO; COUNT(*); SUM(SAL)
;;;;20;;;;;;
5;;10875
;;;;30 6;;;9400
67.ORDER BY
用于對(duì)查詢到的結(jié)果進(jìn)行排序輸出
SQL> select deptno,ename,sal from scott.emp order by deptno,sal desc;
DEPTNO ENAME;SAL
;;;;10 KING;5000
;;;;10 CLARK2450
;;;;10 MILLER; 1300
;;;;20 SCOTT3000
;;;;20 FORD;3000
;;;;20 JONES2975
;;;;20 ADAMS1100
;;;;20 SMITH;800
;;;;30 BLAKE2850
;;;;30 ALLEN1600
;;;;30 TURNER; 1500
;;;;30 WARD;1250
;;;;30 MARTIN; 1250
;;;;30 JAMES;950
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