GROUP BY between dates to count unique users returns more than expected

sql

Solution

If you just want to get a simple count of the distinct users, you can use the `DISTINCT` keyword like this:

SELECT Count(DISTINCT OwnerUserID)
FROM Posts
WHERE (CreationDate BETWEEN '2012-10-19' AND '2012-11-09') AND PostTypeId = 1

The distinct keyword will ensure that you only count each OwnerUserID once - the original question will just return the number of questions that each distinct user asked (which is fairly useless without additional context).

In effect, this query returns a count of the number of rows returned in the original query.

Problem

Using the Stack Exchange Data Explorer I'm trying to figure out how many different users asked questions between 19 October 2012 and 9 November 2012. I've gotten my query to this: ``` SELECT Count(*) FROM Posts WHERE (CreationDate BETWEEN '2012-10-19' AND '2012-11-09') AND PostTypeId = 1 GROUP BY OwnerUserId ``` However, this returns 3,071 rows on Super User (I'm not going to try it on Stack Overflow). This seems way too high. Am I missing something?

Original source