Get last 5 rows from Table for each user [duplicate] - mysql

Question

This question already has answers here:
Select first row in each GROUP BY group?
(20 answers)
Closed 4 years ago.
I need you help with this problem.
Scenario:
Users can vote any number of songs, but I only want to select the last 5 votes per user. I do not want to select the last 5 votes.
Table structure:
Example:
3 users
Karl, voted 10 songs
Robert, voted 6 songs
Joanne, voted 3 songs
I want to get Karls last 5 votes, Roberts last 5 votes and Joannes 3 votes.
Current SQL query:
SELECT songs.genre, songs.title, songs.band, COUNT(*) AS anzahlVotes, users.name
FROM T_Songs AS songs
RIGHT JOIN T_Votes AS votes ON songs.P_Song_id = votes.F_Song_id
LEFT JOIN T_Users AS users ON votes.F_User_id = users.P_User_id
WHERE votes.P_Vote_id IN (
SELECT P_Vote_id
FROM T_Votes
GROUP BY F_User_id
HAVING P_Vote_id > MAX(P_Vote_id)-5
);
But this query doesn't return the right vote count.
Solution (Thanks to Gordon Linoff and Paul Spiegel):
SELECT songs.genre, songs.title, songs.band, COUNT(*) AS anzahlVotes, users.name
FROM T_Songs AS songs
RIGHT JOIN T_Votes AS votes ON songs.P_Song_id = votes.F_Song_id
LEFT JOIN T_Users AS users ON votes.F_User_id = users.P_User_id
WHERE users.nobility_house IS NOT NULL
AND votes.P_Vote_id >= coalesce(
(select votes2.P_Vote_id
from T_Votes votes2
where votes2.F_User_id = votes.F_User_id
order by votes2.P_Vote_id desc
limit 1 offset 4
), 0)
GROUP BY votes.F_User_id

Answer 1

Assuming "last 5" means the five with the highest ids, you can do:
select v.*
from t_votes v
where v.p_vote_id >= (select v2.p_vote_id
from t_votes v2
where v2.f_user_id = v.f_user_id
order by v2.p_vote_id desc
limit 1 offset 4
);
I'll let you figure out how to bring in the columns from the other tables.
EDIT:
If there are fewer than 5 rows:
select v.*
from t_votes v
where v.p_vote_id >= coalesce( (select v2.p_vote_id
from t_votes v2
where v2.f_user_id = v.f_user_id
order by v2.p_vote_id desc
limit 1 offset 4
), p_vote_id
);

Answer 2

You can filter with a join on the same table :
SELECT songs.genre, songs.title, songs.band, COUNT(*) AS anzahlVotes, users.name
FROM T_Songs AS songs
RIGHT JOIN T_Votes AS votes ON songs.P_Song_id = votes.F_Song_id
LEFT JOIN T_Users AS users ON votes.F_User_id = users.P_User_id
LEFT JOIN (
SELECT F_User_id, Max(P_Vote_id)-5 as MaxVoteId
FROM T_Votes
GROUP BY F_User_id
) DF ON ((DF.F_User_id = votes.F_User_id) AND (P_Vote_id >= MaxVoteId));