SQL中的單記錄函數(shù) 1.ASCII 返回與指定的字符對應的十進制數(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),返回對應的字符; SQL> select chr(54740) zhao,chr(65) chr65 from dual; ZH C -- - 趙 A 3.CONCAT 連接兩個字符串; 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 返回字符串并將字符串的第一個字母變?yōu)榇髮? SQL> select initcap('smith') upp from dual; 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(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,默認為1 J 出現(xiàn)的位置,默認為1 SQL> select instr('Oracle traning','ra',1,2) instring from dual; INSTRING --------- 9 6.LENGTH 返回字符串的長度; 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(qū) 6 9999.99 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 -------- aabbccdd8.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 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('HELOVEYOU','HE','I') ------------------------------ i love you 13.SOUNDEX 返回一個與給定的字符串讀音相同的字符串 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 剪掉前面的字符 TRAILING 剪掉后面的字符 假如不指定,默認為空格符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 返回一個數(shù)字反余弦值 SQL> select cosh(20) from dual; COSH(20) --------- 242582598 22.EXP 返回一個數(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 返回一個數(shù)字的對數(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) 返回一個以n1為底n2的對數(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,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 返回一個數(shù)字的正弦值 SQL> select sin(1.57079) from dual; SIN(1.57079) ------------ 1