Story of Hyun

select * from tab;

select * from emp1;

-- 필드 추가

alter table emp1

add (email varchar2(30));

select * from emp1;

-- 이메일 수정

update emp1 set email='ssss@naver.com' where hiredate like '__/02%';

update emp1 set email='aaaaa@nate.com' where ename like '%A%';

update emp1 set email='nnnnn@daum.com' where ename like '%N%';

update emp1 set email='null@hanmail.net' where email is null;

commit;

--------------------------------------------------------------------------------

-- 이름    이메일            아이디 도메인

-- smith  null@hanmail.net  null  hanmail.net

select ename 이름, email 이메일, substr(email, 1, instr(email, '@') -1) 아이디, substr(email, instr(email, '@') +1, length(email)) 도메인 from emp1;

select ename, email, substr(email, 1, instr(email, '@') -1) 아이디, substr(email, instr(email, '@') +1, length(email) - instr(email, '@')) 도메인 from emp1;