SQL中的單記錄函數
1.ASCII
返回與指定的字符對應的十進制數;
SQL>selectascii('A')A,ascii('a')a,ascii('0')zero,ascii('')spacefromdual;
AAZEROSPACE
------------------------------------
65974832
2.CHR
給出整數,返回對應的字符;
SQL>selectchr(54740)zhao,chr(65)chr65fromdual;
ZHC
---
趙A
3.CONCAT
連接兩個字符串;
SQL>selectconcat('010-','88888888')||'轉23'高乾競電話fromdual;
高乾競電話
----------------
010-88888888轉23
4.INITCAP
返回字符串並將字符串的第一個字母變爲大寫;
SQL>selectinitcap('smith')uppfromdual;
UPP
-----
Smith
5.INSTR(C1,C2,I,J)
在一個字符串中搜索指定的字符,返回發現指定的字符的位置;
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,默認爲1
J出現的位置,默認爲1
SQL>selectinstr('oracletraning','ra',1,2)instringfromdual;
INSTRING
---------
9
6.LENGTH
返回字符串的長度;
SQL>selectname,length(name),addr,length(addr),sal,length(to_char(sal))fromgao.nchar_tst;
NAMELENGTH(NAME)ADDRLENGTH(ADDR)SALLENGTH(TO_CHAR(SAL))
---------------------------------------------------------------------------
高乾競3北京市海錠區69999.997
7.LOWER
返回字符串,並將所有的字符小寫
SQL>selectlower('AaBbCcDd')AaBbCcDdfromdual;
AABBCCDD
--------
aabbccdd
8.UPPER
返回字符串,並將所有的字符大寫
SQL>selectupper('AaBbCcDd')upperfromdual;
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>selectlpad(rpad('gao',10,'*'),17,'*')fromdual;
LPAD(RPAD('GAO',1
-----------------
*******gao*******
不夠字符則用*來填滿
10.LTRIM和RTRIM
LTRIM刪除左邊出現的字符串
RTRIM刪除右邊出現的字符串
SQL>selectltrim(rtrim('gaoqianjing',''),'')fromdual;
LTRIM(RTRIM('
-------------
gaoqianjing
11.SUBSTR(string,start,count)
取子字符串,從start開始,取count個
SQL>selectsubstr('13088888888',3,8)fromdual;
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>selectreplace('heloveyou','he','i')fromdual;
REPLACE('H
----------
iloveyou
13.SOUNDEX
返回一個與給定的字符串讀音相同的字符串
SQL>createtabletable1(xmvarchar(8));
SQL>insertintotable1values('weather');
SQL>insertintotable1values('wether');
SQL>insertintotable1values('gao');
SQL>selectxmfromtable1wheresoundex(xm)=soundex('weather');
XM
--------
weather
wether
14.TRIM('s'from'string')
LEADING剪掉前面的字符
TRAILING剪掉後面的字符
如果不指定,默認爲空格符
15.ABS
返回指定值的絕對值
SQL>selectabs(100),abs(-100)fromdual;
ABS(100)ABS(-100)
------------------
100100
16.ACOS
給出反餘弦的值
SQL>selectacos(-1)fromdual;
ACOS(-1)
---------
3.1415927
17.ASIN
給出反正弦的值
SQL>selectasin(0.5)fromdual;
ASIN(0.5)
---------
.52359878
18.ATAN
返回一個數字的反正切值
SQL>selectatan(1)fromdual;
ATAN(1)
---------
.78539816
19.CEIL
返回大於或等於給出數字的最小整數
SQL>selectceil(3.1415927)fromdual;
CEIL(3.1415927)
---------------
4
20.COS
返回一個給定數字的餘弦
SQL>selectcos(-3.1415927)fromdual;
COS(-3.1415927)
---------------
-1
21.COSH
返回一個數字反餘弦值
SQL>selectcosh(20)fromdual;
COSH(20)
---------
242582598
22.EXP
返回一個數字e的n次方根
SQL>selectexp(2),exp(1)fromdual;
EXP(2)EXP(1)
------------------
7.38905612.7182818
23.FLOOR
對給定的數字取整數
SQL>selectfloor(2345.67)fromdual;
FLOOR(2345.67)
--------------
2345
24.LN
返回一個數字的對數值
SQL>selectln(1),ln(2),ln(2.7182818)fromdual;
LN(1)LN(2)LN(2.7182818)
-------------------------------
0.69314718.99999999
25.LOG(n1,n2)
返回一個以n1爲底n2的對數
SQL>selectlog(2,1),log(2,4)fromdual;
LOG(2,1)LOG(2,4)
------------------
02
26.MOD(n1,n2)
返回一個n1除以n2的餘數
SQL>selectmod(10,3),mod(3,3),mod(2,3)fromdual;
MOD(10,3)MOD(3,3)MOD(2,3)
---------------------------
102
27.POWER
返回n1的n2次方根
SQL>selectpower(2,10),power(3,3)fromdual;
POWER(2,10)POWER(3,3)
---------------------
102427
28.ROUND和TRUNC
按照指定的精度進行舍入
SQL>selectround(55.5),round(-55.4),trunc(55.5),trunc(-55.5)fromdual;
ROUND(55.5)ROUND(-55.4)TRUNC(55.5)TRUNC(-55.5)
----------------------------------------------
56-5555-55
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0
SQL>selectsign(123),sign(-100),sign(0)fromdual;
SIGN(123)SIGN(-100)SIGN(0)
----------------------------
1-10
30.SIN
返回一個數字的正弦值
SQL>selectsin(1.57079)fromdual;
SIN(1.57079)
------------
1
31.SIGH
返回雙曲正弦的值
SQL>selectsin(20),sinh(20)fromdual;
SIN(20)SINH(20)
------------------
.91294525242582598
32.SQRT
返回數字n的根
SQL>selectsqrt(64),sqrt(10)fromdual;
SQRT(64)SQRT(10)
------------------
83.1622777
33.TAN
返回數字的正切值
SQL>selecttan(20),tan(10)fromdual;
TAN(20)TAN(10)
------------------
2.2371609.64836083
34.TANH
返回數字n的雙曲正切值
SQL>selecttanh(20),tan(20)fromdual;
TANH(20)TAN(20)
------------------
12.2371609
35.TRUNC
按照指定的精度截取一個數
SQL>selecttrunc(124.1666,-2)trunc1,trunc(124.16666,2)fromdual;
TRUNC1TRUNC(124.16666,2)
---------------------------
100124.16
36.ADD_MONTHS
增加或減去月份
SQL>selectto_char(add_months(to_date('199912','yyyymm'),2),'yyyymm')fromdual;
TO_CHA
------
200002
SQL>selectto_char(add_months(to_date('199912','yyyymm'),-2),'yyyymm')fromdual;
TO_CHA
------
199910
37.LAST_DAY
返回日期的最後一天
SQL>selectto_char(sysdate,'yyyy.mm.dd'),to_char((sysdate)+1,'yyyy.mm.dd')fromdual;
TO_CHAR(SYTO_CHAR((S
--------------------
2004.05.092004.05.10
SQL>selectlast_day(sysdate)fromdual;
LAST_DAY(S
----------
31-5月-04
38.MONTHS_BETWEEN(date2,date1)
給出date2-date1的月份
SQL>selectmonths_between('19-12月-1999','19-3月-1999')mon_betweenfromdual;
MON_BETWEEN
-----------
9
SQL>selectmonths_between(to_date('2000.05.20','yyyy.mm.dd'),to_date('2005.05.20','yyyy.mm.dd'))mon_betwfromdual;
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>selectto_char(sysdate,'yyyy.mm.ddhh24:mi:ss')bj_time,to_char(new_time
2(sysdate,'PDT','GMT'),'yyyy.mm.ddhh24:mi:ss')los_anglesfromdual;
BJ_TIMELOS_ANGLES
--------------------------------------
2004.05.0911:05:322004.05.0918:05:32
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>selectnext_day('18-5月-2001','星期五')next_dayfromdual;
NEXT_DAY
----------
25-5月-01
41.SYSDATE
用來得到系統的當前日期
SQL>selectto_char(sysdate,'dd-mm-yyyyday')fromdual;
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>selectto_char(trunc(sysdate,'hh'),'yyyy.mm.ddhh24:mi:ss')hh,
2to_char(trunc(sysdate,'mi'),'yyyy.mm.ddhh24:mi:ss')hhmmfromdual;
HHHHMM
--------------------------------------
2004.05.0911:00:002004.05.0911:17:00
42.CHARTOROWID
將字符數據類型轉換爲ROWID類型
SQL>selectrowid,rowidtochar(rowid),enamefromscott.emp;
ROWIDROWIDTOCHAR(ROWID)ENAME
----------------------------------------------
AAAAfKAACAAAAEqAAAAAAAfKAACAAAAEqAAASMITH
AAAAfKAACAAAAEqAABAAAAfKAACAAAAEqAABALLEN
AAAAfKAACAAAAEqAACAAAAfKAACAAAAEqAACWARD
AAAAfKAACAAAAEqAADAAAAfKAACAAAAEqAADJONES
43.CONVERT(c,dset,sset)
將源字符串sset從一個語言字符集轉換到另一個目的dset字符集
SQL>selectconvert('strutz','we8hp','f7dec')"conversion"fromdual;
conver
------
strutz
44.HEXTORAW
將一個十六進制構成的字符串轉換爲二進制
45.RAWTOHEXT
將一個二進制構成的字符串轉換爲十六進制
46.ROWIDTOCHAR
將ROWID數據類型轉換爲字符類型
47.TO_CHAR(date,'format')
SQL>selectto_char(sysdate,'yyyy/mm/ddhh24:mi:ss')fromdual;
TO_CHAR(SYSDATE,'YY
-------------------
2004/05/0921:14:41
48.TO_DATE(string,'format')
將字符串轉化爲ORACLE中的一個日期
49.TO_MULTI_BYTE
將字符串中的單字節字符轉化爲多字節字符
SQL>selectto_multi_byte('高')fromdual;
TO
--
高
50.TO_NUMBER
將給出的字符轉換爲數字
SQL>selectto_number('1999')yearfromdual;
YEAR
---------
1999
51.BFILENAME(dir,file)
指定一個外部二進制文件
SQL>insertintofile_tb1values(bfilename('lob_dir1','p_w_picpath1.gif'));
52.CONVERT('x','desc','source')
將x字段或變量的源source轉換爲desc
SQL>selectsid,serial#,username,decode(command,
20,'none',
32,'insert',
43,
5'select',
66,'update',
77,'delete',
88,'drop',
9'other')cmdfromv$sessionwheretype!='background';
SIDSERIAL#USERNAMECMD
------------------------------------------------------
11none
21none
31none
41none
51none
61none
71275none
81275none
920GAOselect
1040GAOnone
53.DUMP(s,fmt,start,length)
DUMP函數以fmt指定的內部數字格式返回一個VARCHAR2類型的值
SQL>colglobal_namefora30
SQL>coldump_stringfora50
SQL>setlin200
SQL>selectglobal_name,dump(global_name,1017,8,5)dump_stringfromglobal_name;
GLOBAL_NAMEDUMP_STRING
--------------------------------------------------------------------------------
ORACLE.WORLDTyp=1Len=12CharacterSet=ZHS16GBK:W,O,R,L,D
54.EMPTY_BLOB()和EMPTY_CLOB()
這兩個函數都是用來對大數據類型字段進行初始化操作的函數
55.GREATEST
返回一組表達式中的最大值,即比較字符的編碼大小.
SQL>selectgreatest('AA','AB','AC')fromdual;
GR
--
AC
SQL>selectgreatest('啊','安','天')fromdual;
GR
--
天
56.LEAST
返回一組表達式中的最小值
SQL>selectleast('啊','安','天')fromdual;
LE
--
啊
57.UID
返回標識當前用戶的唯一整數
SQL>showuser
USER爲"GAO"
SQL>selectusername,user_idfromdba_userswhereuser_id=uid;
USERNAMEUSER_ID
---------------------------------------
GAO25
58.USER
返回當前用戶的名字
SQL>selectuserfromdual;
USER
------------------------------
GAO
59.USEREVN
返回當前用戶環境的信息,opt可以是:
ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZE
ISDBA查看當前用戶是否是DBA如果是則返回true
SQL>selectuserenv('isdba')fromdual;
USEREN
------
FALSE
SQL>selectuserenv('isdba')fromdual;
USEREN
------
TRUE
SESSION
返回會話標誌
SQL>selectuserenv('sessionid')fromdual;
USERENV('SESSIONID')
--------------------
152
ENTRYID
返回會話人口標誌
SQL>selectuserenv('entryid')fromdual;
USERENV('ENTRYID')
------------------
0
INSTANCE
返回當前INSTANCE的標誌
SQL>selectuserenv('instance')fromdual;
USERENV('INSTANCE')
-------------------
1
LANGUAGE
返回當前環境變量
SQL>selectuserenv('language')fromdual;
USERENV('LANGUAGE')
----------------------------------------------------
SIMPLIFIEDCHINESE_CHINA.ZHS16GBK
LANG
返回當前環境的語言的縮寫
SQL>selectuserenv('lang')fromdual;
USERENV('LANG')
----------------------------------------------------
ZHS
TERMINAL
返回用戶的終端或機器的標誌
SQL>selectuserenv('terminal')fromdual;
USERENV('TERMINA
----------------
GAO
VSIZE(X)
返回X的大小(字節)數
SQL>selectvsize(user),userfromdual;
VSIZE(USER)USER
-----------------------------------------
6SYSTEM
60.AVG(DISTINCT|ALL)
all表示對所有的值求平均值,distinct只對不同的值求平均值
SQLWKS>createtabletable3(xmvarchar(8),salnumber(7,2));
語句已處理。
SQLWKS>insertintotable3values('gao',1111.11);
SQLWKS>insertintotable3values('gao',1111.11);
SQLWKS>insertintotable3values('zhu',5555.55);
SQLWKS>commit;
SQL>selectavg(distinctsal)fromgao.table3;
AVG(DISTINCTSAL)
----------------
3333.33
SQL>selectavg(allsal)fromgao.table3;
AVG(ALLSAL)
-----------
2592.59
61.MAX(DISTINCT|ALL)
求最大值,ALL表示對所有的值求最大值,DISTINCT表示對不同的值求最大值,相同的只取一次
SQL>selectmax(distinctsal)fromscott.emp;
MAX(DISTINCTSAL)
----------------
5000
62.MIN(DISTINCT|ALL)
求最小值,ALL表示對所有的值求最小值,DISTINCT表示對不同的值求最小值,相同的只取一次
SQL>selectmin(allsal)fromgao.table3;
MIN(ALLSAL)
-----------
1111.11
63.STDDEV(distinct|all)
求標準差,ALL表示對所有的值求標準差,DISTINCT表示只對不同的值求標準差
SQL>selectstddev(sal)fromscott.emp;
STDDEV(SAL)
-----------
1182.5032
SQL>selectstddev(distinctsal)fromscott.emp;
STDDEV(DISTINCTSAL)
-------------------
1229.951
64.VARIANCE(DISTINCT|ALL)
求協方差
SQL>selectvariance(sal)fromscott.emp;
VARIANCE(SAL)
-------------
1398313.9
65.GROUPBY
主要用來對一組數進行統計
SQL>selectdeptno,count(*),sum(sal)fromscott.empgroupbydeptno;
DEPTNOCOUNT(*)SUM(SAL)
---------------------------
1038750
20510875
3069400
66.HAVING
對分組統計再加限制條件
SQL>selectdeptno,count(*),sum(sal)fromscott.empgroupbydeptnohavingcount(*)>=5;
DEPTNOCOUNT(*)SUM(SAL)
---------------------------
20510875
3069400
SQL>selectdeptno,count(*),sum(sal)fromscott.emphavingcount(*)>=5groupbydeptno;
DEPTNOCOUNT(*)SUM(SAL)
---------------------------
20510875
3069400
67.ORDERBY
用於對查詢到的結果進行排序輸出
SQL>selectdeptno,ename,salfromscott.emporderbydeptno,saldesc;
DEPTNOENAMESAL
----------------------------
10KING5000
10CLARK2450
10MILLER1300
20SCOTT3000
20FORD3000
20JONES2975
20ADAMS1100
20SMITH800
30BLAKE2850
30ALLEN1600
30TURNER1500
30WARD1250
30MARTIN1250
30JAMES950
出處：http://zhangronghua.cnblogs.com
本文版權歸作者和博客園共有，歡迎轉載，但未經作者同意必須保留此段聲明，且在文章頁面明顯位置給出原文連接，否則保留追究法律責任的權利。