Sqlite query comparison multiple times - sql

Question

I have the following schemas (sqlite):
JournalArticle(articleID, title, journal, volume, year, month)
ConferenceArticle(articleID, title, conference, year, location)
Person(name, affiliation)
Author(name, articleID)
I'm trying to get the names of all authors who have number of conferences articles >= journal articles in every year from 2000-2018 inclusive. If an author has 0 articles in each category in a year then the condition still holds. The only years that matter are 2000-2018
The query would be much easier if it was over all years since I could count the journal articles and conferences articles and make a comparison then get the names. However, I'm stuck when trying to check over every year 2000-2018.
I of course don't want to do repetitive queries over all the years. I feel like I may need to group by year but I'm not sure. So far I've been able to get all articles of both types from 2000-2018 as one large table but I'm not sure what to do next.:
select articleID, year
from JournalArticle
where year >= 2000 and year <= 2018
union
select articleID, year
from ConferenceArticle
where year >= 2000 and year <= 2018

Answer 1

Hmmm. Let's start by getting a count for each author and year:
select a.name, year, sum(is_journal), sum(is_conference)
from ((select ja.article_id, ja.year, 1 as is_journal, 0 as is_conference
from journalarticle ja
) union all
(select ca.article_id, ca.year, 0 as is_journal, 1 as is_conference
from conferencearticle ca
)
) jc join
authors a
on a.article_id = jc.article_id
group by a.name, jc.year
Now, you can aggregate again to match the years that match the conditions:
select ay.name
from (select a.name, year, sum(is_journal) as num_journal, sum(is_conference) as num_conference
from ((select ja.article_id, ja.year, 1 as is_journal, 0 as is_conference
from journalarticle ja
) union all
(select ca.article_id, ca.year, 0 as is_journal, 1 as is_conference
from conferencearticle ca
)
) jc join
authors a
on a.article_id = jc.article_id
group by a.name, jc.year
) ay
where (jc.year >= 2000 and jc.year <= 2018) and
num_journal >= num_conference
group by ay.name;

Answer 2

Sounds like you could use a COALESCE in the GROUP BY
SELECT a.name,
COALESCE(j.year, c.year) as "year",
COUNT(j.articleID) AS JournalArticles,
COUNT(c.articleID) AS ConferenceArticles
FROM Author a
LEFT JOIN JournalArticle j ON (j.articleID = a.articleID AND j.year BETWEEN 2000 AND 2018)
LEFT JOIN ConferenceArticle c ON (c.articleID = a.articleID AND c.year BETWEEN 2000 AND 2018)
WHERE (j.year IS NOT NULL OR c.year IS NOT NULL)
GROUP BY a.name, COALESCE(j.year, c.year)
HAVING COUNT(c.articleID) >= COUNT(j.articleID)