lemmy/migrations/2019-03-30-212058_create_po.../up.sql

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-- Rank = ScaleFactor * sign(Score) * log(1 + abs(Score)) / (Time + 2)^Gravity
CREATE OR REPLACE FUNCTION hot_rank (score numeric, published timestamp without time zone)
RETURNS integer
AS $$
BEGIN
-- hours_diff:=EXTRACT(EPOCH FROM (timezone('utc',now()) - published))/3600
RETURN floor(10000 * log(greatest (1, score + 3)) / power(((EXTRACT(EPOCH FROM (timezone('utc', now()) - published)) / 3600) + 2), 1.8))::integer;
END;
$$
LANGUAGE plpgsql;
CREATE VIEW post_view AS
with all_post AS (
SELECT
p.*,
(
SELECT
name
FROM
user_
WHERE
p.creator_id = user_.id) AS creator_name,
(
SELECT
name
FROM
community
WHERE
p.community_id = community.id) AS community_name,
(
SELECT
removed
FROM
community c
WHERE
p.community_id = c.id) AS community_removed,
(
SELECT
count(*)
FROM
comment
WHERE
comment.post_id = p.id) AS number_of_comments,
coalesce(sum(pl.score), 0) AS score,
count(
CASE WHEN pl.score = 1 THEN
1
ELSE
NULL
END) AS upvotes,
count(
CASE WHEN pl.score = - 1 THEN
1
ELSE
NULL
END) AS downvotes,
hot_rank (coalesce(sum(pl.score), 0), p.published) AS hot_rank
FROM
post p
LEFT JOIN post_like pl ON p.id = pl.post_id
GROUP BY
p.id
)
SELECT
ap.*,
u.id AS user_id,
coalesce(pl.score, 0) AS my_vote,
(
SELECT
cf.id::bool
FROM
community_follower cf
WHERE
u.id = cf.user_id
AND cf.community_id = ap.community_id) AS subscribed,
(
SELECT
pr.id::bool
FROM
post_read pr
WHERE
u.id = pr.user_id
AND pr.post_id = ap.id) AS read,
(
SELECT
ps.id::bool
FROM
post_saved ps
WHERE
u.id = ps.user_id
AND ps.post_id = ap.id) AS saved
FROM
user_ u
CROSS JOIN all_post ap
LEFT JOIN post_like pl ON u.id = pl.user_id
AND ap.id = pl.post_id
UNION ALL
SELECT
ap.*,
NULL AS user_id,
NULL AS my_vote,
NULL AS subscribed,
NULL AS read,
NULL AS saved
FROM
all_post ap;