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你碰到的问题可能已经在社区中被别的人已经问过，即使没有MySQL学习教程，你也可以提出问题或通过Google来搜索答案。社区的相关负责人士：“MySQL社区是活跃、友好和内容渊博的。”oracle|函数SQL中的单纪录函数
1.ASCII
前往与指定的字符对应的十进制数;
SQL>selectascii(A)A,ascii(a)a,ascii(0)zero,ascii()spacefromdual;
AAZEROSPACE
------------------------------------
65974832
2.CHR
给出整数,前往对应的字符;
SQL>selectchr(54740)zhao,chr(65)chr65fromdual;
ZHC
---
赵A
3.CONCAT
毗连两个字符串;
SQL>selectconcat(010-,88888888)||转23高乾竞德律风fromdual;
高乾竞德律风
----------------
010-88888888转23
4.INITCAP
前往字符串并将字符串的第一个字母变成年夜写;
SQL>selectinitcap(smith)uppfromdual;
UPP
-----
Smith
5.INSTR(C1,C2,I,J)
在一个字符串中搜刮指定的字符,前往发明指定的字符的地位;
C1被搜刮的字符串
C2但愿搜刮的字符串
I搜刮的入手下手地位,默许为1
J呈现的地位,默许为1
SQL>selectinstr(oracletraning,ra,1,2)instringfromdual;
INSTRING
---------
9
6.LENGTH
前往字符串的长度;
SQL>selectname,length(name),addr,length(addr),sal,length(to_char(sal))fromgao.nchar_tst;
NAMELENGTH(NAME)ADDRLENGTH(ADDR)SALLENGTH(TO_CHAR(SAL))
---------------------------------------------------------------------------
高乾竞3北京市海锭区69999.997
7.LOWER
前往字符串,并将一切的字符小写
SQL>selectlower(AaBbCcDd)AaBbCcDdfromdual;
AABBCCDD
--------
aabbccdd
8.UPPER
前往字符串,并将一切的字符年夜写
SQL>selectupper(AaBbCcDd)upperfromdual;
UPPER
--------
AABBCCDD
9.RPAD和LPAD(粘贴字符)
RPAD在列的右侧粘贴字符
LPAD在列的右边粘贴字符
SQL>selectlpad(rpad(gao,10,*),17,*)fromdual;
LPAD(RPAD(GAO,1
-----------------
*******gao*******
不敷字符则用*来填满
10.LTRIM和RTRIM
LTRIM删除右边呈现的字符串
RTRIM删除右侧呈现的字符串
SQL>selectltrim(rtrim(gaoqianjing,),)fromdual;
LTRIM(RTRIM(
-------------
gaoqianjing
11.SUBSTR(string,start,count)
取子字符串,从start入手下手,取count个
SQL>selectsubstr(13088888888,3,8)fromdual;
SUBSTR(
--------
08888888
12.REPLACE(string,s1,s2)
string但愿被交换的字符或变量
s1被交换的字符串
s2要交换的字符串
SQL>selectreplace(heloveyou,he,i)fromdual;
REPLACE(H
----------
iloveyou
13.SOUNDEX
前往一个与给定的字符串读音不异的字符串
SQL>createtabletable1(xmvarchar(8));
SQL>insertintotable1values(weather);
SQL>insertintotable1values(wether);
SQL>insertintotable1values(gao);
SQL>selectxmfromtable1wheresoundex(xm)=soundex(weather);
XM
--------
weather
wether
14.TRIM(sfromstring)
LEADING剪失落后面的字符
TRAILING剪失落前面的字符
假如不指定,默许为空格符
15.ABS
前往指定值的相对值
SQL>selectabs(100),abs(-100)fromdual;
ABS(100)ABS(-100)
------------------
100100
16.ACOS
给出反余弦的值
SQL>selectacos(-1)fromdual;
ACOS(-1)
---------
3.1415927
17.ASIN
给出归正弦的值
SQL>selectasin(0.5)fromdual;
ASIN(0.5)
---------
.52359878
18.ATAN
前往一个数字的归正切值
SQL>selectatan(1)fromdual;
ATAN(1)
---------
.78539816
19.CEIL
前往年夜于或即是给出数字的最小整数
SQL>selectceil(3.1415927)fromdual;
CEIL(3.1415927)
---------------
4
20.COS
前往一个给定命字的余弦
SQL>selectcos(-3.1415927)fromdual;
COS(-3.1415927)
---------------
-1
21.COSH
前往一个数字反余弦值
SQL>selectcosh(20)fromdual;
COSH(20)
---------
242582598
22.EXP
前往一个数字e的n次方根
SQL>selectexp(2),exp(1)fromdual;
EXP(2)EXP(1)
------------------
7.38905612.7182818
23.FLOOR
对给定的数字取整数
SQL>selectfloor(2345.67)fromdual;
FLOOR(2345.67)
--------------
2345
24.LN
前往一个数字的对数值
SQL>selectln(1),ln(2),ln(2.7182818)fromdual;
LN(1)LN(2)LN(2.7182818)
-------------------------------
0.69314718.99999999
25.LOG(n1,n2)
前往一个以n1为底n2的对数
SQL>selectlog(2,1),log(2,4)fromdual;
LOG(2,1)LOG(2,4)
------------------
02
26.MOD(n1,n2)
前往一个n1除以n2的余数
SQL>selectmod(10,3),mod(3,3),mod(2,3)fromdual;
MOD(10,3)MOD(3,3)MOD(2,3)
---------------------------
102
27.POWER
前往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
依照指定的精度举行舍进
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
取数字n的标记,年夜于0前往1,小于0前往-1,即是0前往0
SQL>selectsign(123),sign(-100),sign(0)fromdual;
SIGN(123)SIGN(-100)SIGN(0)
----------------------------
1-10
30.SIN
前往一个数字的正弦值
SQL>selectsin(1.57079)fromdual;
SIN(1.57079)
------------
1
31.SIGH
前往双曲正弦的值
SQL>selectsin(20),sinh(20)fromdual;
SIN(20)SINH(20)
------------------
.91294525242582598
32.SQRT
前往数字n的根
SQL>selectsqrt(64),sqrt(10)fromdual;
SQRT(64)SQRT(10)
------------------
83.1622777
33.TAN
前往数字的正切值
SQL>selecttan(20),tan(10)fromdual;
TAN(20)TAN(10)
------------------
2.2371609.64836083
34.TANH
前往数字n的双曲正切值
SQL>selecttanh(20),tan(20)fromdual;
TANH(20)TAN(20)
------------------
12.2371609
35.TRUNC
依照指定的精度截取一个数
SQL>selecttrunc(124.1666,-2)trunc1,trunc(124.16666,2)fromdual;
TRUNC1TRUNC(124.16666,2)
---------------------------
100124.16
36.ADD_MONTHS
增添或减往月份
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
前往日期的最初一天
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)
给出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)
给出在this时区=other时区的日期和工夫
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)
给出日期date和礼拜x以后盘算下一个礼拜的日期
SQL>selectnext_day(18-5月-2001,礼拜五)next_dayfromdual;
NEXT_DAY
----------
25-5月-01
41.SYSDATE
用来失掉体系确当前日期
SQL>selectto_char(sysdate,dd-mm-yyyyday)fromdual;
TO_CHAR(SYSDATE,
-----------------
09-05-2004日曜日
trunc(date,fmt)依照给出的请求将日期截断,假如fmt=mi暗示保存分,截断秒
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
将字符数据范例转换为ROWID范例
SQL>selectrowid,rowidtochar(rowid),enamefromscott.emp;
ROWIDROWIDTOCHAR(ROWID)ENAME
----------------------------------------------
AAAAfKAACAAAAEqAAAAAAAfKAACAAAAEqAAASMITH
AAAAfKAACAAAAEqAABAAAAfKAACAAAAEqAABALLEN
AAAAfKAACAAAAEqAACAAAAfKAACAAAAEqAACWARD
AAAAfKAACAAAAEqAADAAAAfKAACAAAAEqAADJONES
43.CONVERT(c,dset,sset)
将源字符串sset从一个言语字符集转换到另外一个目标dset字符集
SQL>selectconvert(strutz,we8hp,f7dec)"conversion"fromdual;
conver
------
strutz
44.HEXTORAW
将一个十六进制组成的字符串转换为二进制
45.RAWTOHEXT
将一个二进制组成的字符串转换为十六进制
46.ROWIDTOCHAR
将ROWID数据范例转换为字符范例
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)
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>selectto_multi_byte(高)fromdual;
TO
--
高
50.TO_NUMBER
将给出的字符转换为数字
SQL>selectto_number(1999)yearfromdual;
YEAR
---------
1999
51.BFILENAME(dir,file)
指定一个内部二进制文件
SQL>insertintofile_tb1values(bfilename(lob_dir1,image1.gif));
52.CONVERT(x,desc,source)
将x字段或变量的源source转换为desc
SQL>selectsid,serial#,username,decode(command,
20,none,
32,insert,
43,
5select,
66,update,
77,delete,
88,drop,
9other)cmdfromv$sessionwheretype!=background;
SIDSERIAL#USERNAMECMD
------------------------------------------------------
11none
21none
31none
41none
51none
61none
71275none
81275none
920GAOselect
1040GAOnone
53.DUMP(s,fmt,start,length)
DUMP函数以fmt指定的外部数字格局前往一个VARCHAR2范例的值
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()
这两个函数都是用来对年夜数据范例字段举行初始化操纵的函数
55.GREATEST
前往一组表达式中的最年夜值,即对照字符的编码巨细.
SQL>selectgreatest(AA,AB,AC)fromdual;
GR
--
AC
SQL>selectgreatest(啊,安,天)fromdual;
GR
--
天
56.LEAST
前往一组表达式中的最小值
SQL>selectleast(啊,安,天)fromdual;
LE
--
啊
57.UID
前往标识以后用户的独一整数
SQL>showuser
USER为"GAO"
SQL>selectusername,user_idfromdba_userswhereuser_id=uid;
USERNAMEUSER_ID
---------------------------------------
GAO25
58.USER
前往以后用户的名字
SQL>selectuserfromdual;
USER
------------------------------
GAO
59.USEREVN
前往以后用户情况的信息,opt能够是:
ENTRYID,SESSIONID,TERMINAL,ISDBA,LABLE,LANGUAGE,CLIENT_INFO,LANG,VSIZE
ISDBA检察以后用户是不是是DBA假如是则前往true
SQL>selectuserenv(isdba)fromdual;
USEREN
------
FALSE
SQL>selectuserenv(isdba)fromdual;
USEREN
------
TRUE
SESSION
前往会话标记
SQL>selectuserenv(sessionid)fromdual;
USERENV(SESSIONID)
--------------------
152
ENTRYID
前往会话生齿标记
SQL>selectuserenv(entryid)fromdual;
USERENV(ENTRYID)
------------------
0
INSTANCE
前往以后INSTANCE的标记
SQL>selectuserenv(instance)fromdual;
USERENV(INSTANCE)
-------------------
1
LANGUAGE
前往以后情况变量
SQL>selectuserenv(language)fromdual;
USERENV(LANGUAGE)
----------------------------------------------------
SIMPLIFIEDCHINESE_CHINA.ZHS16GBK
LANG
前往以后情况的言语的缩写
SQL>selectuserenv(lang)fromdual;
USERENV(LANG)
----------------------------------------------------
ZHS
TERMINAL
前往用户的终端或呆板的标记
SQL>selectuserenv(terminal)fromdual;
USERENV(TERMINA
----------------
GAO
VSIZE(X)
前往X的巨细(字节)数
SQL>selectvsize(user),userfromdual;
VSIZE(USER)USER
-----------------------------------------
6SYSTEM
60.AVG(DISTINCT|ALL)
all暗示对一切的值求均匀值,distinct只对分歧的值求均匀值
SQLWKS>createtabletable3(xmvarchar(8),salnumber(7,2));
语句已处置。
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)
求最年夜值,ALL暗示对一切的值求最年夜值,DISTINCT暗示对分歧的值求最年夜值,不异的只取一次
SQL>selectmax(distinctsal)fromscott.emp;
MAX(DISTINCTSAL)
----------------
5000
62.MIN(DISTINCT|ALL)
求最小值,ALL暗示对一切的值求最小值,DISTINCT暗示对分歧的值求最小值,不异的只取一次
SQL>selectmin(allsal)fromgao.table3;
MIN(ALLSAL)
-----------
1111.11
63.STDDEV(distinct|all)
求尺度差,ALL暗示对一切的值求尺度差,DISTINCT暗示只对分歧的值求尺度差
SQL>selectstddev(sal)fromscott.emp;
STDDEV(SAL)
-----------
1182.5032
SQL>selectstddev(distinctsal)fromscott.emp;
STDDEV(DISTINCTSAL)
-------------------
1229.951
64.VARIANCE(DISTINCT|ALL)
求协方差
SQL>selectvariance(sal)fromscott.emp;
VARIANCE(SAL)
-------------
1398313.9
65.GROUPBY
次要用来对一组数举行统计
SQL>selectdeptno,count(*),sum(sal)fromscott.empgroupbydeptno;
DEPTNOCOUNT(*)SUM(SAL)
---------------------------
1038750
20510875
3069400
66.HAVING
对分组统计再加限定前提
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
用于对查询到的了局举行排序输入
SQL>selectdeptno,ename,salfromscott.emporderbydeptno,saldesc;
DEPTNOENAMESAL
----------------------------
10KING5000
10CLARK2450
10MILLER1300
20SCOTT3000
20FORD3000
20JONES2975
20ADAMS1100
20SMITH800
30BLAKE2850
30ALLEN1600
30TURNER1500
30WARD1250
30MARTIN1250
30JAMES950
Oracle最经常使用功效函数典范汇总ChinaITLab搜集收拾2004-6-1410:58:00 *SQLGroupFunction
*
s(numcanbeacolumnorex
pression)
(nullvaluesareign
*
ored,defaultbetweendistin
ctandallisall)
********************
***************
****************************
****************
AVG([distinctorall]num)
--averagevalue
COUNT(distinctorall]num)
--numberofvalues
MAX([distinctorall
]num) --maximumvalue
MAX([distinctorall]num)
--minimumvalue
STDDEV([distinctor
all]num) --standarddevi
ation
SUM([distinctorall
]num) --sumofvalues
VARIANCE([distincto
rall]num)--varianceofv
alues
********************************
***********************
************************
*MiscellaneaousFunctions:
*
********************
***************
****************************
****************
DECODE(expr,srch1,
return1[,srch2,return2...]
,default]
--ifnosearchmatchest
heexpressionthenthedefaultisreturned,
--otherwise,
thefirstsearchthatmatch
eswillcause
--thecorres
pondingreturnvaluetober
eturned
DUMP(column_name[,fmt[,start_p
os[,length]]])
--returnsan
column
internaloracleformat,used
forgettinginfoabouta
--formatoptions:8=oc
tal,10=decimel,16=hex,17=characters
--returntype
codes:1=varchar2,2=n
umber,8=long,12=date,
-- 23=raw,
24=longraw,69=rowid,
96=char,106=mlslabel
GREATEST(expr[,expr2[,expr3...]] --returnsthelargestval
ueofallexpressions
LEAST(expr[,expr2[,expr3...]] --returnsthe
smallestvalueofallexpre
ssions
NVL(expr1,expr2 --ifexpr1isnotnull,i
tisreturned,otherwiseexpr2isreturned
SQLCODE --returnssqlerrorcode
query,
oflasterror. Cannotbeuseddirectlyin
--valuemust
besettolocalvariablefir
st
SQLERRM --returnssql
inquery,
errormessageoflasterror
. Cannotbeuseddirectly
--valuemustbesettolo
calvariablefirst
UID --returnstheuseridof
theuseryouareloggedonas
--usefulins
electinginformationfromlo
wlevelsystables
USER --returnsthe
usernameoftheuseryoua
reloggedonas
USERENV(option) --returnsinf
ormationabouttheuseryou
areloggedonas
--options:E
NTRYID,SESSIONID,TERMINAL,
LANGUAGE,LABEL,OSDBA
-- (
alloptionsnotavailablein
allOracleversions)
VSIZE(expr) --returnsthenumberofb
ytesusedbytheexpression
--usefulins
electinginformationaboutt
ablespacerequirements
********************
***************
****************************
****************
*SQLDateFunctions(dtreprese
*
ntsoracledateandtime)
*(functionsreturn
*
anoracledateunlessotherw
isespecified)
********************************
***********************
************************
ADD_MONTHS(dt,num)
--addsnummonthsto
dt(numcanbenegative)
LAST_DAY(dt)
--lastdayofmonthin
monthcontainingdt
MONTHS_BETWEEN(dt1,dt2)--retu
dt2
rnsfractionalvalueofmonthsbetweendt1,
NEW_TIME(dt,tz1,tz
zone2
2) --dt=dateintimezo
ne1,returnsdateintime
NEXT_DAY(dt,str) --date
etc..)
offirst(str)afterdt(str=Monday,
SYSDATE --presentsystemdate ROUND(dt[,fmt] --roun
dsdtasspecifiedbyformatfmt
TRUNC(dt[,fmt]
--truncatesdtasspe
cifiedbyformatfmt
********************************
***********************
************************
*NumberFunctions:
*
********************************
***********************
************************
ABS(num) --absolute
valueofnum
CEIL(num) --smallestinteger>or=num
COS(num) --cosine(n
um),numinradians
COSH(num)
--hyperboliccosine(num)
EXP(num)
--eraisedtothenumpowe
r
FLOOR(num) --largest
integer<or=num
LN(num) --natural
logarithmofnum
LOG(num2,num1) --logarith
mbasenum2ofnum1
MOD(num2,num1) --remainde
rofnum2/num1
POWER(num2,num1)
--num2raisedtothenum1
power
ROUND(num1[,num2] --num1rou
ndedtonum2decimelplaces(default0)
SIGN(num) --signof
num*1,0ifnum=0
SIN(num)
--sin(num),numinradians
SINH(num) --hyperbolicsine(num) SQRT(num) --squarerootofnum TAN(num) --tangent(
num),numinradians
TANH(num)
--hyperbolictangent(num)
TRUNC(num1[,num2] --truncate
num1tonum2decimelplaces(default0)
********************************
***********************
************************
*StringFunctions,
*
StringResult:
********************************
***********************
************************
(num) --ASCII
characterfornum
CHR(num)
--ASCIIcharacterforn
um
CONCAT(str1,str2) --str1
concatenatedwithstr2(sameasstr1||str2)
INITCAP(str)
--capitalizefirstlett
erofeachwordinstr
LOWER(str) --strw
ithalllettersinlowercase
LPAD(str1,num[,str2])--left
spaces)
padstr1tolengthnumwithstr2(default
LTRIM(str[,set])
--removesetfromleft
sideofstr(defaultspaces)
NLS_INITCAP(str[,nl
s_val])--sameasinitcapf
ordifferentlanguages
NLS_LOWER(str[,nls_
val]) --sameaslowerfor
differentlanguages
REPLACE(str1,str2[,str3])--r
eplacesstr2withstr3instr1
--
deletesstr2fromstr1ifstr3isomitted
RPAD(str1,num[,str
(defaultspaces)
2]) --rightpadstr1to
lengthnumwithstr2
RTRIM(str[,set])
spaces)
--removesetfrom
rightsideofstr(default
SOUNDEX(str)
--phoneticrepresen
tationofstr
SUBSTR(str,num2[,n
um1]) --substringofstr,
startingwithnum2,
--
omitted)
num1characters(toendofstrifnum1is
SUBSTRB(str,num2[,
bytes
num1]) --sameassubstrbu
tnum1,num2expressedin
TRANSLATE(str,set1,
set2) --replacesset1in
strwithset2
--
truncated
ifset2islongerthanset1,itwillbe
UPPER(str)
--strwithalllett
ersinuppercase
********************
***************
****************************
****************
*StringFunctions,
*
NumericResult:
********************************
***********************
************************
ASCII(str)
--ASCIIvalueofstr
INSTR(str1,str2[,num1[,num2]]
)--positionofnum2thoccurrenceof
--str2instr1,startingatnum1
--(num1,num2defaultto1)
INSTRB(str1,str2[,num1[num2]]
)--sameasinstr,bytevaluesfornum1,num2
LENGTH(str)
--numberof
charactersinstr
LENGTHB(str)
--numberofbytesinstr
NLSSORT(str[,nls_val])
--nls_valbytevalueofstr
********************************
***********************
************************
*SQLConversionFunctions
*
********************************
***********************
************************
CHARTOROWID(str)
--convertsstrtoROWID
CONVERT(str,chr_set2[,chr_set1
])--convertsstrtochr_set2
characterset
--chr_set1
defaultisthedatbase
HEXTORAW(str)
--convertshexstringva
luetointernalrawvalues
RAWTOHEX(raw_val) --convert
srawhexvaluetohexstringvalue
ROWIDTOCHAR(rowid)
--convertsrowidto18ch
aracterstringformat
TO_CHAR(expr[,fmt])
fmt
--convertsexpr(dateorn
umber)toformatspecifiedby
TO_DATE(str[,fmt])
--convertsstringtodat
e
TO_MULTI_BYTE(str) --convert
ssinglebytestringtomultibytestring
TO_NUMBER(str[,fmt])--convert
sstrtoanumberformattedbyfmt
TO_SINGLE_BYTE(str)
--convertsmultibytest
ringtosinglebytestring
********************************
***********************
************************
*SQLDateFormats
*
********************
***************
****************************
****************
BC,B.C. BCindicator AD,A.D. ADindicator CC,SCC Cent
uryCode(SCCincludesspace
or-sign)
YYYY,SYYYY 4digityear(SY
YYYincludesspaceor-sign)
IYYY 4digitISOyear Y,YYY 4digityearwithcomma YYY,YY,orY last3,2,or1
digitofyear
YEAR,SYEAR yearspelledout
(SYEARincludesspaceor-sign)
RR last2digitsof
yearinpriorornextcentury
Q quarteroryear,1to4 MM month-from01to12 MONTH monthspelledout MON month3letterabbreviation RM romannumeralformonth WW weekofyear,1to53 IW ISOweekofyear
,1to52or1to53
W weekofmonth,1
to5(week1begins1stdayofthemonth)
D dayofweek,1to7 DD dayofmonth,1to31 DDD dayofyear,1to366 DAY dayofweekspel
ledout,ninecharactersrightpadded
DY dayabbreviation J #of
dayssinceJan1,4712BC
HH,HH12 hourofday,1to12 HH24 hourofday,0to23 MI minuteofhour,0to59 SS secondofminute,0to59 SSSSS seco
ndspastmidnight,0to8639
9
AM,A.M. amindicator PM,P.M. pmindicator anypuctuation punc
tuationbetweenformatitems
,asinDD/MM/YY
anytext textbetweenformatitems TH conv
erts1to1st,2to2nd,
andsoon
SP converts1too
ne,2totwo,andsoon
SPTH converts1toF
IRST,2toSECOND,andsoon
FX fill
exact:usesexactpattern
matching
FM fillmode :tog
glessuppressionofblanksinoutput
MySQL已经为支持所有最流行的Web2.0语言做好了准备，诸如Ruby、Ajax等，当然还有PHP。有的业界分析师说过，“每一个Web2.0公司实质上就是一个数据库公司。 |
|
|Archiver|手机版|仓酷云
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发表于 2015-1-16 22:41:06
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发表于 2015-3-11 14:29:14