select ename from emp where instr(ename,'R')=0;
select translate(ename,'A','a') from emp;
select replace(ename,'A','a') from emp;
select ename from emp where instr(ename,select ename from emp where instr(ename,'R')=0;
select translate(ename,'A','a') from emp;
select replace(ename,'A','a') from emp;
select ename from emp where instr(ename,