Finding bad Narutos

While looking for Naruto posts
(= overlooked accepted answers well worthy of upvotes),
I noticed some odd false positives,
selfie answers,
where the user who asked the question accepted his own answer under suspicious circumstances.

I'd call suspicious circumstance the case when other answers exist with positive votes,
while the selfie has

• Good selfies may actually deserve upvotes

Also keep in mind that the data of SEDE is not up to date,
so when you find already flagged or upvoted selfie accepts,
it doesn't mean the query is broken.

It looks good to me. Just a minor funky format thing going on here in the very first CTE.

WITH AcceptedAnswers AS (
  SELECT Id, ParentId, Score, OwnerUserId, CreationDate
  FROM Posts
  WHERE PostTypeId = 2
    AND (@userId < 0 OR OwnerUserId = @userId)
    AND (@username = '' OR OwnerUserId IN (
        SELECT Id
        FROM Users
        WHERE DisplayName = @username))

You might want to consider some newlines and extra indentation for that last AND.

WITH AcceptedAnswers AS (
  SELECT Id, ParentId, Score, OwnerUserId, CreationDate
  FROM Posts
  WHERE PostTypeId = 2
    AND (@userId < 0 OR OwnerUserId = @userId)
    AND (@username = '' 
        OR OwnerUserId IN (
            SELECT Id
            FROM Users
            WHERE DisplayName = @username
            )
        )

StackExchange Code Review Q#79174, answer score: 2