As per this answer comments can't be downvoted.
VoteTypeId 3 means downvote on a given post. referred answer
My Assumption: Comments should not be downvoted and therefore Votes table on SEDE StackoverFlow (StackExchange Data Explorer) should not have entries with VoteTypeId = 3 for any comment as a PostId.
I ran the following query on SEDE StackOverflow to test my assumption. Following query extracts all the comments of answers of a given QuestionId and finds their entries in Votes table.
select * from votes where postid in (select id from comments where postid in (select id from posts where parentid = 7172459))
I found that there are several entries for some comments with VoteTypeId = 3.
Can anyone please explain if the VoteTypeIds have different notion when considered them in the context of a Comment?