On the rocks / Poured over ice
Is there any difference between "poured over ice" and "on the rocks"? If no, then which expression is used more often in everyday conversation, in your opinion?
For example, when somebody orders whiskey with ice cubes, what are they supposed to say?
1. Whiskey on the rocks, please;
2. Whiskey over ice, please;
3. Whiskey, iced, please;
or maybe there is another way?