SQL Insert select update delete

//Insert

insert into emp

values (2, '미처','CLERK', 7782, sysdate, 5000, 150, 30)

//select 이용해서 insert

insert into emp(empno, ename)

select employee_id, substr(first_name,1,10)

from employees

where department_id = 110

//update

update emp

set sal=600,

    deptno = 30

where empno in (205, 206)

rollback;

update emp

set sal = ( select avg(sal) from emp)

 where empno =1

commit

//Delete

delete from emp

where empno = 1

commit

delete from emp

where empno in (select employee_id from employees)

commit