alter table dept drop primary key;

create index dept_deptno_idx on dept(deptno);

exec dbms_stats.gather_table_stats(user, 'dept');

# Sort Unique ۷̼
select * from emp
where  deptno in (select deptno from dept);


select b.*
from  (select /*+ no_merge */ distinct deptno from dept order by deptno) a, emp b
where  b.deptno = a.deptno ;


-- Ŭ 9i
select /*+ ordered use_nl(emp) */ * from emp
where  deptno in (select /*+ unnest */ deptno from dept);

-- Ŭ 10g 
select /*+ leading(dept@qb1) use_nl(emp) */ * from emp 
where deptno in (select /*+ unnest  qb_name(qb1) */ deptno from dept);


#   
select /*+ leading(emp) */ * from emp
where  deptno in (select /*+ unnest nl_sj */ deptno from dept);

select /*+ leading(emp) */ * from emp
where  deptno in (select /*+ unnest hash_sj */ deptno from dept);

select /*+ leading(emp) */ * from emp
where  deptno in (select /*+ unnest merge_sj */ deptno from dept);

