SQL Tuning : Using Hints

• Good hints vs Bad hints
• good hint : ordered
• Automatic Query Rewrite with Hint
• use_concat

select ename from emp
where
    deptno=10
or
   sal< 5000
or
   job='CLERK'

The first option is to create a bitmap index on the 3 columns, the second option is to use use_concat hint :

select /*+ use_concat */ ename from emp
where
    deptno=10
or
   sal< 5000
or
   job='CLERK'