A wounded Zombie finder, or: how to find the almost dead undead?

Question

The Zombies are on their way to eat our statistics. Fortunately, we have a way to get rid of them: our votes. However, we need to find them first. The /unanswered section is too large and contains many strong enemies where we have to write a review first. But the StackExchange Data Explorer can sniff almost dead Zombies from a mile.

For this, we need a fitting query. This is what I've tried:

SELECT 
  q.Id AS [Post Link],
  MAX(a.Score) AS [Best answer score]
FROM 
  Posts q
JOIN 
  Posts a ON a.ParentId = q.Id
WHERE 
      q.PostTypeId = 1  
  AND q.AnswerCount > 0
  AND q.AcceptedAnswerId IS NULL
  AND a.PostTypeId = 2
GROUP BY 
  q.Id
HAVING 
 MAX(a.Score) = 0

You can run and find the query on SEDE.

It searches for questions (q.PostTypeId = 1) that have at least one answer, no accepted answer, and the maximum score of all its answers is 0. The resulting list can then be checked for fast Zombie removal.

Is there something that is utterly wrong? Or can this weapon help us in our fight against the undead?

Answer 1

Not utterly wrong, but

q.PostTypeId = 1 

and

AND a.PostTypeId = 2

are superfluous. The only post types with a non-null value in ParentId are answers (see the Database schema documentation), and their values are the ids of questions, so the join already takes care of this.

I'd slightly misunderstood the objective of the query at first, because questions with answers with negative scores, like this one also appear on /unanswered. But you want to review the answers to see if they're worthy of an upvote. Then, you might as well drop the second column (MAX(a.Score) AS [Best answer score]) because you know it's going to be zero.