Oracle：函数
基本函数：
SQL> select ascii(‘a’),ascii(‘Z’) from dual;
ASCII(‘A’) ASCII(‘Z’)
———- ———-
97 90
SQL>
SQL> select chr(65) from dual;
C
–
A
SQL> select chr(122) from dual;
C
–
z
SQL>
SQL> select chr(66) from dual;
C
–
B
SQL>
SQL> select concat(‘Hello ‘,’World’) from dual;
CONCAT(‘HEL
———–
Hello World
SQL>
SQL> select initcap(‘adamhuan’) from dual;
INITCAP(
——–
Adamhuan
SQL>
SQL> select instr(‘let is do it’,’i’,2,2) from dual;
INSTR(‘LETISDOIT’,’I’,2,2)
————————–
11
SQL>
说明：字符i在字符串中从第二个字符开始出现第二次的位置是第十一个字符。
SQL> select length(‘adamhuan’) from dual;
LENGTH(‘ADAMHUAN’)
——————
8
SQL>
SQL> select lower(‘ADAMHUAN’) from dual;
LOWER(‘A
——–
adamhuan
SQL>
SQL> select upper(‘adamhuan’) from dual;
UPPER(‘A
——–
ADAMHUAN
SQL>
SQL> select upper(‘adamhuan’) from dual;
UPPER(‘A
——–
ADAMHUAN
SQL> select lpad(‘dkseven’,9,’@’) from dual;
LPAD(‘DKS
———
@@dkseven
SQL> select lpad(‘dkseven’,2,’#’) from dual;
LP
—
dk
SQL> select rpad(‘dkseven’,9,’@’) from dual;
RPAD(‘DKS
———
dkseven@@
SQL> select rpad(‘dkseven’,2,’#’) from dual;
RP
—
dk
SQL>
SQL> select ltrim(‘adamhuan’,’a’) from dual;
LTRIM(‘
——-
damhuan
SQL>
SQL> select replace(‘adamhuan’,’a’,’e’) from dual;
REPLACE(
——–
edemhuen
SQL>
SQL> select rowid,deptno,dname,loc from dept;
ROWID DEPTNO DNAME LOC
—————— ———- ————– ————-
AAAVRCAAEAAAACHAAA 10 ACCOUNTING NEW YORK
AAAVRCAAEAAAACHAAB 20 RESEARCH DALLAS
AAAVRCAAEAAAACHAAC 30 SALES CHICAGO
AAAVRCAAEAAAACHAAD 40 OPERATIONS BOSTON
SQL> select * from dept where rowid=’AAAVRCAAEAAAACHAAB’;
DEPTNO DNAME LOC
———- ————– ————-
20 RESEARCH DALLAS
SQL> select * from dept where rowid=chartorowid(‘AAAVRCAAEAAAACHAAB’);
DEPTNO DNAME LOC
———- ————– ————-
20 RESEARCH DALLAS
SQL>
——————
Done。
