oracle常用函数（1）

select ascii('A') A,ascii('z') a,ascii('12') 一打,ascii(' ') kg from dual;

select chr(65) A,chr(122) z from dual;

select concat('熊大','熊二') constr from dual;--熊大熊二

select initcap('boat') upperfirst from dual;--Boat

select upper('boat') upperall from dual t;--BOAT

select lower('BoaT') lowerall from dual;--boat

select instr('zheshigeceshi','sh',-2,1) str from dual;--11
select instr('zheshigeceshi','sh',1,2) str from dual;--11

select length('boat') len from dual;--4

select rpad('boat',10,'*') from dual t;--boat******
select lpad('boat',10,'*') from dual t;--******boat

select ltrim('boat','bo') from dual;--at
select ltrim('booooobbbbobat','bo') from dual t;--at
select rtrim('boat','at') from dual;--bo
select rtrim('boaaaaaaaaatttttttaat','at') from dual;--bo

select substr('boatisgood',3,100) subs from dual;--atisgood
select substr('boatisgood',3) subs from dual;--atisgood
select substr('boatisgood',-3) subs from dual;--ood

select replace('nba hupu 步行街怎么没有了','步行街','BXJ') from dual;--nba hupu BXJ怎么没有了