Only way to write this SQL JOIN question? - sql

Question

I wrote this sql query and it seems to work great but im not sure if it is the correct way to write it or if there is another better way to write it:
SELECT
art.artid, users.userid
FROM
art LEFT JOIN users
ON
art.userid = users.userid
WHERE
(SELECT COUNT(1) FROM art WHERE art.userid = users.userid) > 5 AND
users.active = '1' AND
art.active = '1' AND
art.status = '0' AND
art.pricesek > 0 GROUP BY users.userid ORDER BY RAND()
It gets the users from users table that are active and has 5 or more artworks in the art table. It also checks to see that artwork is active, status of artwork is set to 0 "for sale" and price is more then 0. Then it groups results by userid in a random order.
Is this the correct way to write this or is there another way.
"All input is hardcoded so no userinput will be sent into database, so not worried about injections (should i be worried even if its hardcoded?)."

Answer 1

I made a small change in your code. Instead of using (SELECT COUNT (1) FROM art WHERE art.userid = users.userid)> 5 I put it in Having clause.
SELECT art.artid, users.userid
FROM art LEFT JOIN users ON art.userid = users.userid
WHERE users.active = '1' AND art.active = '1' AND
art.status = '0' AND art.pricesek > 0
GROUP BY users.userid, art.artid
HAVING COUNT(users.userid) > 5
ORDER BY RAND()

Answer 2

Your query has problems at many levels. The most obvious is that the GROUP BY clause is inconsistent with the SELECT. That should be generating an error.
It gets the users from users table that are active and has 5 or more artworks in the art table.
I would instead suggest aggregating the art table before joining:
SELECT u.userid
FROM users u JOIN
(SELECT a.userid, COUNT(*) as cnt
FROM art a
WHERE a.active = 1 AND
a.status = 0 AND
a.pricesek > 0
GROUP BY a.userid
) a
ON a.userid = u.userid
WHERE a.cnt > 5 AND u.active = 1
ORDER BY RAND();
Notes:
LEFT JOIN is not appropriate. In order to count the number of artworks, the JOIN must find at least 1 (really 6) matching rows.
It makes no sense to return a.artid. If you need an example, you could use min(a.artid) in the subquery. If you want all of them, then you would need to specify how to return them, but a JSON, array, or string aggregation function would be used n the subquery.
The values "1" and "0" look like numbers, so I removed the single quotes, so I assume the columns are numbers. Compare numbers to numbers and strings to strings. Try to avoid mixing the two.