Oracle forced index using HINT

Oracle forced index using HINT

First of all, it depends on whether your Oracle optimizer uses RBO or CBO,
(1) If RBO is used, it will be performed in the Rule Order.
(2) If CBO is used, you can use the HINT method to modify it.

Syntax:SELECT/* + index (table IndexName )*/
If an alias is used in a query statement, the table in the preceding statement must be an alias. Otherwise, a forced index is not executed.

Example:

Select/* + INDEX (t IDX_DATE) */from student t where t. birthday> to_date ('2017-12-28 00:00:00 ', 'yyyy-mm-dd hh24: mi: ss') and t. birthday <to_date ('2017-12-28 23:59:59 ', 'yyyy-mm-dd hh24: mi: ss') group by t. class