Three consecutive days

keeps note of the person who called and on what date.

This is just another example of one of the many fine short questions that occasionally get submitted to Ask The Expert. A short question is best because it allows for leeway, even creativity, in interpreting the requirements.

For instance, which three consecutive days? Let's arbitrarily choose the three days prior to today, because today's not over yet (and the person may yet still call). Furthermore, if the person called six times yesterday, but not at all in the two days before yesterday, does that count? Let's arbitrarily say that there must be at least one call per day.

Finally, let's note that there have to be more than three calls in total.

Here's the solution:

select person_name
     , count(*)    as callcount
  from calls
 where calldate 
    >= current_date - interval '3' day
   and calldate 
     < current_date 
group
    by person_name
having count(distinct calldate) = 3
   and count(*) > 3

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