select * from Posts where Posts.PostTypeId = 2 and (EXISTS (select 1 from PostTags where PostTags.PostId = Posts.ParentId and PostTags.TagId = 3)) and Posts.OwnerUserId = 352552
And this similar attempt produces the same:
select * from Posts where Posts.PostTypeId = 2 and ParentId IN (select PostId from PostTags where PostTags.TagId = 3) and Posts.OwnerUserId = 352552
Clearly I'm making at least one invalid assumption about the data model. Can someone point me in the right direction?