These are easier to answer if you ask complete sentences. I'll flesh them out to show the difference.
The dog has been sitting there all day.
The dog has sat there all day.
Their meaning is the same. Somewhere around the start of the day, the dog sat "there", and he is still there now.
The only difference is that the first sentence somewhat emphasises the duration of the activity, while the second just states the fact.
Student or Learner