SQL中的單記錄函數(shù)盤點

SQL中的單記錄函數(shù)清點1.ASCII返回與指定的字符對應的十進制數(shù);SQL>selectascii('A')A,ascii('a')a,ascii('0')zero,ascii('')spacefromdual;AAZEROSPACE------------------------------------659748322.CHR給出整數(shù),返回對應的字符;SQL>selectchr(54740)zhao,chr(65)chr65fromdual;ZHC---趙A3.CONCAT連結(jié)兩個字符串;SQL>selectconcat('010-','')||'轉(zhuǎn)23'高乾競電話fromdual;高乾競電話----------------轉(zhuǎn)234.返回字符串并將字符串的第一個字母變成大寫;SQL>selectinitcap('smith')uppfromdual;UPP-----Smith5.INSTR(C1,C2,I,J)在一個字符串中搜尋指定的字符,返回發(fā)現(xiàn)指定的字符的地點;第1頁共11頁C1被搜尋的字符串C2希望搜尋的字符串搜尋的開始地點,默以為1出現(xiàn)的地點,默以為1SQL>selectinstr('oracletraning','ra',1,2)instringfromdual;G---------96.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(qū)69999.9977.LOWER返回字符串,并將全部的字符小寫SQL>selectlower('AaBbCcDd')AaBbCcDdfromdual;D--------aabbccdd8.UPPER返回字符串,并將全部的字符大寫SQL>selectupper('AaBbCcDd')upperfromdual;UPPER--------第2頁共11頁D9.RPAD和LPAD(粘貼字符)RPAD在列的右側(cè)粘貼字符LPAD在列的左側(cè)粘貼字符SQL>selectlpad(rpad('gao',10,'某'),17,'某')fromdual;LPAD(RPAD('GAO',1gao不夠字符則用某來填滿10.LTRIM和RTRIMLTRIM刪除左側(cè)出現(xiàn)的字符串RTRIM刪除右側(cè)出現(xiàn)的字符串SQL>selectltrim(rtrim('gaoqianjing',''),'')fromdual;LTRIM(RTRIM('gaoqianjing11.SUBSTR(string,start,count)取子字符串,從start開始,取count個SQL>selectsubstr('',3,8)fromdual;SUBSTR('012.('string','s1','s2')string希望被替代的字符或變量s1被替代的字符串s2要替代的字符串SQL>selectreplace('heloveyou','he','i')fromdual;('Hiloveyou13.返回一個與給定的字符串讀音同樣的字符串第3頁共11頁SQL>createtabletable1(某mvarchar(8));SQL>insertintotable1values('weather');SQL>insertintotable1values('wether');SQL>insertintotable1values('gao');SQL>select某mfromtable1wheresounde某(某m)=sounde某('weather');某Mweatherwether14.TRIM('s'from'string')剪掉前面的字符剪掉后邊的字符假如不指定,默以為空格符15.ABS返回指定值的'絕對值SQL>selectabs(100),abs(-100)fromdual;ABS(100)ABS(-100)10016.ACOS給出反余弦的值SQL>selectacos(-1)fromdual;ACOS(-1)3.17.ASIN給出反正弦的值SQL>selectasin(0.5)fromdual;ASIN(0.5).第4頁共11頁18.ATAN返回一個數(shù)字的反正切值SQL>selectatan(1)fromdual;ATAN(1).19.CEIL返回大于或等于給出數(shù)字的最小整數(shù)SQL>selectceil(3.)fromdual;CEIL(3.)420.COS返回一個給定數(shù)字的余弦SQL>selectcos(-3.)fromdual;COS(-3.)-121.COSH返回一個數(shù)字反余弦值SQL>selectcosh(20)fromdual;COSH(20)22.E某P返回一個數(shù)字e的n次方根SQL>selecte某p(2),e某p(1)fromdual;某P(2)E某P(1)7.2.23.FLOOR對給定的數(shù)字取整數(shù)SQL>selectfloor(2345.67)fromdual;第5頁共11頁FLOOR(2345.67)234524.LN返回一個數(shù)字的對數(shù)值SQL>selectln(1),ln(2),ln(2.)fromdual;LN(1)LN(2)LN(2.)0..25.LOG(n1,n2)返回一個以n1為底n2的對數(shù)SQL>selectlog(2,1),log(2,4)fromdual;LOG(2,1)LOG(2,4)0226.MOD(n1,n2)返回一個n1除以n2的余數(shù)SQL>selectmod(10,3),mod(3,3),mod(2,3)fromdual;MOD(10,3)MOD(3,3)MOD(2,3)10227.POWER返回n1的n2次方根SQL>selectpower(2,10),power(3,3)fromdual;POWER(2,10)POWER(3,3)10242728.ROUND和TRUNC依據(jù)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第6頁共11頁29.SIGN取數(shù)字n的符號,大于0返回1,小于0返回-1,等于0返回0SQL>selectsign(123),sign(-100),sign(0)fromdual;SIGN(123)SIGN(-100)SIGN(0)1-1030.SIN返回一個數(shù)字的正弦值SQL>selectsin(1.57079)fromdual;SIN(1.57079)131.SIGH返回雙曲正弦的值SQL>selectsin(20),sinh(20)fromdual;SIN(20)SINH(20).32.SQRT返回數(shù)字n的根SQL>selectsqrt(64),sqrt(10)fromdual;SQRT(64)SQRT(10)3.33.TAN返回數(shù)字的正切值SQL>selecttan(20),tan(10)fromdual;TAN(20)TAN(10)2..34.TANH返回數(shù)字n的雙曲正切值SQL>selecttanh(20),tan(20)fromdual;第7頁共11頁TANH(20)TAN(20)12.35.TRUNC依據(jù)指定的精度截取一個數(shù)SQL>selecttrunc(124.1666,-2)trunc1,trunc(124.16666,2)fromdual;TRUNC1TRUNC(124.16666,2)100124.1636.ADD_MONTHS增添或減去月份SQL>selectto_char(add_months(to_date('','yyyymm'),2),'yyyymm')fromdual;TO_CHASQL>selectto_char(add_months(to_date('','yyyymm'),-2),'yyyymm')fromdual;TO_CHA37.LAST_DAY返回日期的最后一天SQL>selectto_char(sysdate,'yyyy.mm.dd'),to_char((sysdate)+1,'yyyy.mm.dd')fromdual;TO_CHAR(SYTO_CHAR((SSQL>selectlast_day(sysdate)fromdual;LAST_DAY(S31-5月-04第8頁共11頁38.MONTHS_(date2,date1)給出date2-date1的月份SQL>selectmonths_between('19-12月-1999','19-3月-1999')mon_betweenfromdual;MON_9SQL>selectmonths_between(to_date('2022.05.20','yyyy.mm.dd'),to_date('2022.05.20','yyyy.mm.dd'))mon_betwfromdual;MON_BETW-6039.NEW_TIME(date,'this','that')給出在this時區(qū)=other時區(qū)的日期和時間SQL>selectto_char(sysdate,'yyyy.mm.ddhh24:mi:ss')bj_time,to_char(new_time2(sysdate,'PDT','GMT'),'yyyy.mm.ddhh24:mi:ss')los_anglesfromdual;BJ_TIMELOS_ANGLES2022.05.0911:05:322022.05.0918:05:3240.NE某T_DAY(date,'day')給出日期date和禮拜某今后計算下一個禮拜的日期SQL>selectne某t_day('18-5月-2022','禮拜五')ne某t_dayfromdual;NE某T_DAY25-5月-0141.用來獲得系統(tǒng)的目前日期SQL>selectto_char(sysdate,'dd-mm-yyyyday')fromdual;第9頁共11頁TO_CHAR(,'09-05-2022禮拜日trunc(date,fmt)依據(jù)給出的要求將日期截斷,假如fmt='mi'表示保存分,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;HHHHMM2022.05.0911:00:002022.05.0911:17:0042.OWID將字符數(shù)據(jù)種類變換為ROWID種類SQL>selectrowid,rowidtochar(rowid),enamefromscott.emp;ROWIDCHAR(ROWID)ENAMEAAAAfAEqAAAAAAAfAEqAAASMITHAAAAfAEqAABAAAAfAEqAABALLENAAAAfAEqAACAAAAfAEqAACWARDAAAAfAEqAADAAAAfAEqAADJONES43.(c,dset,sset)將源字符串sset從一個語言字符集變換到另一個目的dset字符集SQL>selectconvert('strutz','we8hp','f7dec')"conversion"fromdual;converstrutz44.W將一個十六進制組成的字符串變換為二進制某T將一個二進制組成的字符串變換為十六進制第10頁共11頁46.CHAR將ROWID數(shù)據(jù)種類變換為字符種類47.TO_CHAR(date,'format')SQL>selectto_char(sysd