For example:
set autot trace exp stat select /*+ INDEX(MYTABLE MY_IDX1) */ min(entry_num) from sales.sales_log where sold_date >= '05.12.2017';
Which gave me the following plan:
----------------------------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop | ----------------------------------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | 11 | 9 (0)| 00:00:01 | | | | 1 | SORT AGGREGATE | | 1 | 11 | | | | | | 2 | PARTITION RANGE ITERATOR | | 1 | 11 | 9 (0)| 00:00:01 | 1 | 13 | |* 3 | TABLE ACCESS BY LOCAL INDEX ROWID BATCHED| SALES | 1 | 11 | 9 (0)| 00:00:01 | 1 | 13 | | 4 | INDEX FULL SCAN | MY_IDX1 | 3 | | 3 (0)| 00:00:01 | 1 | 13 | -----------------------------------------------------------------------------------------------------------------------------
Line 4 of the explain plan output shows that the index MY_IDX1 is being used.