SQL中的單記錄函式

1.ASCII 返回與指定的字元對應的十進位制數;
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 連線兩個字串;
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,返回發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 .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(貼上字元)
RPAD 在列的右邊貼上字元
LPAD 在列的左邊貼上字元
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RTRIM
LTRIM 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('HELOVEYOU','HE','I')
------------------------------
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
--------
weather
wether

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 返回一個數字的反正切值
SQL> select atan(1) from dual;
ATAN(1)
---------
.78539816

19.CEIL 返回大於或等於給出數字的最小整數
SQL> select ceil(3.1415927) from dual;
CEIL(3.1415927)
---------------
4

20.COS 返回一個給定數字的餘弦
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 返回一個數字的對數值
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)
--------- ---------

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 返回一個數字的正弦值
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 返回數字的正切值
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
按照指定的精度擷取一個數
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
------
200002
SQL> 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 2004.05.10
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.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 將字元資料型別轉換為ROWID型別
SQL> select rowid,rowidtochar(rowid),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)
將源字串 sset從一個語言字符集轉換到另一個目的dset字符集
SQL> select convert('strutz','we8hp','f7dec') "conversion" from dual;
conver
------
strutz

44.HEXTORAW 將一個十六進位制構成的字串轉換為二進位制

45.RAWTOHEXT 將一個二進位制構成的字串轉換為十六進位制

46.ROWIDTOCHAR 將ROWID資料型別轉換為字元型別

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制檔案
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desc
SQL> 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

53.DUMP(s,fmt,start,length)
DUMP函式以fmt指定的內部數字格式返回一個VARCHAR2型別的值
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.WORLD Typ=1 Len=12 CharacterSet=ZHS16GBK: W,O,R,L,D

54.EMPTY_BLOB()和EMPTY_CLOB()
這兩個函式都是用來對大資料型別欄位進行初始化操作的函式

55.GREATEST
返回一組表示式中的最大值,即比較字元的編碼大小.
SQL> select greatest('AA','AB','AC') from dual;
GR
--
AC
SQL> select greatest('啊','安','天') from dual;
GR
--
天

56.LEAST
返回一組表示式中的最小值
SQL> select least('啊','安','天') from dual;
LE
--
啊

57.UID
返回標識當前使用者的唯一整數
SQL> show user
USER 為"GAO"
SQL> select username,user_id from dba_users where user_id=uid;
USERNAME USER_ID
------------------------------ ---------
GAO 25

58.USER
返回當前使用者的名字
SQL> select user from dual;
USER
------------------------------
GAO

59.USEREVN
返回當前使用者環境的資訊,opt可以是:
ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZE
ISDBA 檢視當前使用者是否是DBA如果是則返回true
SQL> select userenv('isdba') from dual;
USEREN
------
FALSE
SQL> select userenv('isdba') from dual;
USEREN
------
TRUE
SESSION
返回會話標誌
SQL> select userenv('sessionid') from dual;
USERENV('SESSIONID')
--------------------
152
ENTRYID
返回會話人口標誌
SQL> select userenv('entryid') from dual;
USERENV('ENTRYID')
------------------
0
INSTANCE
返回當前INSTANCE的標誌
SQL> select userenv('instance') from dual;
USERENV('INSTANCE')
-------------------
1
LANGUAGE
返回當前環境變數
SQL> select userenv('language') from dual;
USERENV('LANGUAGE')
----------------------------------------------------
SIMPLIFIED CHINESE_CHINA.ZHS16GBK
LANG
返回當前環境的語言的縮寫
SQL> select userenv('lang') from dual;
USERENV('LANG')
----------------------------------------------------
ZHS
TERMINAL
返回使用者的終端或機器的標誌
SQL> select userenv('terminal') from dual;
USERENV('TERMINA
----------------
GAO
VSIZE(X)
返回X的大小(位元組)數
SQL> select vsize(user),user from dual;
VSIZE(USER) USER
----------- ------------------------------
6 SYSTEM

Oracle SQL 內建函式大全(轉)

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