PHP SQL order by multiple rows - mysql

I have a table called 'scorelist' with the following results:
ID USER_ID SCORE SEASON
-----------------------------
1 1 35 3
2 1 45 2
3 2 80 3
4 2 85 1
5 3 65 2
I want to make a score list where I show the scores of the users but only of their last played season.
Result should be:
ID USER_ID SCORE SEASON
-----------------------------
3 2 80 3
5 3 65 2
1 1 35 2
I use the following code:
SELECT * FROM scorelist
WHERE season = (
SELECT season FROM scorelist ORDER BY season DESC LIMIT 1
)
GROUP BY user_id
ORDER BY score DESC;
But then I only get the results of season 3, so a lot of users are not shown.
I also tried:
SELECT * FROM scorelist group by user_id ORDER BY score DESC, season DESC
But this is also not working.
I hope you can help me.

The subquery gets the latest season for each user. If you join to that you get your desired results
SELECT s1.*
FROM scorelist s1
JOIN
(
SELECT user_id, max(season) AS season
FROM scorelist
GROUP BY user_id
) s2 ON s1.user_id = s2.user_id AND s1.season = s2.season

Since MySQL 8.0 you can use window function row_number to solve this problem:
WITH ordered_scorelist AS (
SELECT
scorelist.*,
row_number() over (partition by USER_ID order by SEASON DESC) rn
FROM scorelist
) SELECT
USER_ID, SCORE, SEASON
FROM ordered_scorelist
WHERE rn = 1
ORDER BY SCORE DESC;
MySQL row_number test

Related

Query to return to 4th to 8th rank in a leaderboard?

I have been given a leaderboard, I need to return the row correspond to 4th to 8th rank in a leaderboard?
id name score
1 gongy 3001
2 urandom 2401
3 eduardische 2477
4 Gassa 2999
5 bcc32 2658
6 Alex_2oo8 6000
7 mirosuaf 2479
8 Sparik 2399
9 thomas_holmes 2478
The query I have is not being accepted
select b.name from
(
select a.name as name ,a.score as score from
(
select name,score from leaderboard order by score desc limit 8
)a
order by a.score
limit 5
) b
order by b.score desc;
You can use LIMIT OFFSET
select id,
name,
score
from leaderboard
order by score desc
limit 4 offset 3 ; --- fetch 4 records, begin with record 4 (OFFSET 3)
https://dbfiddle.uk/Ys-3jC4L
Above query skips the first 4 rows and limit the result to 4 make it from 4th to 8th
select x.id,x.name,x.score
from
(
select id,name,score,
row_number()over(order by score desc)xcol
from your_table
)x where x.xcol >=3 and x.xcol<=8
May be something like this ?

Select multiple tables with only unique users and ordered by latest id

I have 2 tables, first one is called members:
id name show
1 John 1
2 Wil 1
3 George 1
4 Chris 1
Second is called score:
id user_id score
1 1 90
2 1 70
3 2 55
4 3 30
5 3 40
6 3 100
7 4 30
user_id from score is the id of members.
What I want is to show a scorelist with unique members.id, ordered by score.score and order by the latest score.id.
I use the following code:
SELECT members.id, members.show, score.id, score.user_id, score.score FROM members
INNER JOIN score ON score.user_id = members.id
WHERE members.show = '1'
GROUP BY score.user_id
ORDER BY score.score DESC, score.id DESC
The output is not ordered by the latest score.id, but it does show only unique user_id's:
id user_id score
1 1 90
3 2 55
4 3 30
7 4 30
It should be like:
id user_id score
6 3 100
2 1 70
3 2 55
7 4 30
I hope you can help me
You could use:
with cte as (
select id,
user_id,
score,
row_number() over(partition by user_id order by id desc) as row_num
from score
) select cte.id,user_id,score
from cte
inner join members m on cte.user_id=m.id
where row_num=1
order by score desc;
Demo
If your MySQL server doesn't support windows function, use:
select s.id,s.user_id,s.score
from score s
inner join members m on s.user_id=m.id
where s.id in (select max(id) as id
from score
group by user_id
)
order by score desc;
Demo

Trouble using group by to get a max value across two tables

I have been trying to solve a problem for a very long time- days- and I am not making any progress. Basically, I have two tables, players and matches. Each player in players has a unique player_id, as well as a group_id that identifies which group he/she belongs to. Each match in matches has the player_ids of two players in it, first_player and second_player, who are always from the same group. first_score corresponds to the score that first_player scores and second_score corresponds to the score that second_player scores. A match is won by who ever scores more. Here are the two tables:
create table players (
player_id integer not null unique,
group_id integer not null
);
create table matches (
match_id integer not null unique,
first_player integer not null,
second_player integer not null,
first_score integer not null,
second_score integer not null
);
Now what I am trying to do is to get the players with the most wins from each group, their group ID as well as the number of wins. So, for example, if there are three groups, the result would be something like:
Group Player Wins
1 24 23
2 13 25
3 34 20
Here's what I have right now
SELECT p1.group_id AS Group, p1.player_id AS Player, COUNT(*) AS Wins
FROM players p1, matches m1
WHERE (m1.first_player = p1.player_id AND m1.first_score > m1.second_score)
OR (m1.second_player = p1.player_id AND m1.second_score > m1.first_score)
GROUP BY p1.group_id
HAVING COUNT(*) >= (
SELECT COUNT(*)
FROM players p2, matches m2
WHERE p2.group_id = p1.group_id AND
((m2.first_player = p2.player_id AND m2.first_score > m2.second_score)
OR (m2.second_player = p2.player_id AND m2.second_score > m2.first_score))
)
My idea is to only select players whose wins are greater than, or equal to, the wins of all other players in his group. There is some syntactic problem with my query. I think I am using GROUP BY incorrectly as well.
There is also the issue of a tie in the number of wins, where I should just get the player with the least player_id. But I haven't even gotten to that point yet. I would really appreciate your help, thanks!
EDIT 1
I have a few sample data that I am running my query against.
SELECT * FROM players gives me this:
Player_ID Group_ID
100 1
200 1
300 1
400 2
500 2
600 3
700 3
SELECT * FROM matches gives me this:
match_id first_player second_player first_score second_score
1 100 200 10 20
2 200 300 30 20
3 400 500 30 10
4 500 400 20 20
5 600 700 20 10
So, the query should return:
Group Player Wins
1 200 2
2 400 1
3 600 1
Running the query as is returns the following error:
ERROR: column "p1.player_id" must appear in the GROUP BY clause or be used in an aggregate function
Now I understand that I have to specify player_id in the GROUP BY clause if I want to use it in the SELECT (or HAVING) statement, but I do not wish to group by player ID, only by the group ID.
Even if I do add p1.player_id to GROUP BY in my outer query, I get...the correct answer actually. But I am a bit confused. Doesn't Group By aggregate the table according to that column? Logically speaking, I only want to group by p1.group_id.
Also, if I were to have multiple players in a group with the highest number of wins, how can I just keep the one with the lowest player_id?
Edit 2
If I change the matches table to such that for Group 1, there are two players with 1 win each, the query result omits Group 1 from the result altogether.
So, if my matches table is:
match_id first_player second_player first_score second_score
1 100 200 10 20
2 200 300 10* 20
3 400 500 30 10
4 500 400 20 20
5 600 700 20 10
I would expect the result to be
Group Player Wins
1 200 1
1 300 1
2 400 1
3 600 1
However, I get the following:
Group Player Wins
2 400 1
3 600 1
Note that the desired result is
Group Player Wins
1 200 1
2 400 1
3 600 1
Since I wish to only take the player with the least player_id in the case of a draw.
WITH first_players AS (
SELECT group_id,player_id,SUM(first_score) AS scores FROM players p LEFT JOIN matches m ON p.player_id=m.first_player GROUP BY group_id,player_id
),
second_players AS (
SELECT group_id,player_id,SUM(second_score) AS scores FROM players p LEFT JOIN matches m ON p.player_id=m.second_player GROUP BY group_id,player_id
),
all_players AS (
WITH al AS (
SELECT group_id, player_id, scores FROM first_players
UNION ALL
SELECT group_id, player_id, scores FROM second_players
)
SELECT group_id, player_id,COALESCE(SUM(scores),0) AS scores FROM al GROUP BY group_id, player_id
),
players_rank AS (
SELECT *,
ROW_NUMBER() OVER(PARTITION BY group_id ORDER BY scores DESC, player_id ASC) AS score_rank,
ROW_NUMBER() OVER(PARTITION BY scores ORDER BY player_id ASC) AS id_rank FROM all_players ORDER BY group_id
)
SELECT group_id, player_id AS winner_id FROM players_rank WHERE score_rank=1 AND id_rank=1
Results
group_id winner_id
1 45
2 20
3 40
Try it Out
try like below
with cte as
(
select p.Group_ID,t1.winplayer,t1.numberofwin
row_number()over(partition by p.Group_ID order by t1.numberofwin desc,t1.winplayer) rn from players p join
(
SELECT count(*) as numberofwin,
case when first_score >second_score then first_player
else second_player end as winplayer
FROM matches group by case when first_score >second_score then first_player
else second_player end
) t1 on p.Player_ID =t1.winplayer
) select * from cte where rn=1
It works when you add the player_id in the GROUP BY because you know each player plays only in one group. So you group by the player in a certain group. That is why, logically, you can add the player_id to the GROUP BY.

MySQL: Find the average value per entry for the last x records

I'm trying to figure out how to grab the average rating for each salesperson over their last 100 ratings if they are currently employed, and if they have an average rating less than 3 (out of 5).
I have the following tables (leaving out information that isn't needed in the query):
users
id name employed
-----------------------
1 John 1
2 Sue 1
3 Bob 0
...
sales
id users_id
------------------
100 3
101 2
102 3
103 1
...
ratings
sales_id rating
-----------------
100 4
101 5
102 5
103 2
...
The current query I have searches everything and returns the average for all orders ever but I want it to only grab the most recent 100 ratings (or less if the salesperson hasn't sold that many items), still excluding anyone that is no longer employed or has a rating for their last 100 orders greater than 3. This is the current query:
SELECT u.name, avg(r.rating) as avg_rating, count(r.rating)
FROM users AS u
JOIN sales AS s ON s.users_id = u.id
JOIN ratings AS r ON r.sales_id = s.id
WHERE u.employed = 1
GROUP BY u.id
HAVING avg_rating <= 3;
Any help would be great! Thanks! :D
You can use my sql variables to keep track of the number of ratings so that you can get only recent 100 ratings , ordering by sales_id so you get recent ratings.
SQL FIDDLE DEMO
SELECT T.name, avg(T.rating) as avg_rating, count(T.rating)
FROM
(
SELECT u.name, r.rating, #num := if (#name = name, #num+1, 1) as rn,
#name:= name as var_name
FROM users AS u
JOIN sales AS s ON s.users_id = u.id
JOIN ratings AS r ON r.sales_id = s.id
AND u.employed = 1
JOIN ( select #name :='' , #num :=1) var
order by sales_id desc
)T
where T.rn <=100
GROUP BY T.name
HAVING avg_rating <= 3

How to get rank in MySQL from 2 tables?

I have 2 different tables in my database by the name of: rank, settings.
Here is how each table looks like with a few records in them:
Table #rank:
id points userid
-- ----- ------
1 500 1
2 300 2
3 900 3
4 1500 4
5 100 5
6 700 6
7 230 7
8 350 8
9 850 9
10 150 10
Table #settings:
userid active
------ ------
1 0
2 1
3 1
4 1
5 1
6 0
7 1
8 1
9 0
10 1
I want to get the rank of a specific user by user_id from the rank table ordering by their points. Also I would Only want to include the users in the ranking results, if they have active = 1 set in the settings table.
I have a simple ranking query, but it is not really effective, because it does include everyone even if the user is not active:
SELECT * FROM
(SELECT #sort:=#sort+1 AS sort, points, userid
FROM rank,
(SELECT #sort := 0) s
ORDER BY points DESC) t
WHERE userid= 8
Any idea, how could I achieve my goals here?
Few sub queries. First gets all the users who are active in the right order. That is used as a source for another query to add the rank. Then this is used as the source for the points and rank for the userid you are actually interested in
SELECT sort, points
FROM
(
SELECT #sort:=#sort + 1 AS sort, points, userid
FROM
(
SELECT rank.points, rank.userid
FROM rank
INNER JOIN settings
ON rank.userid = settings.userid
WHERE settings.active = 1
ORDER BY points DESC
) sub0
CROSS JOIN (SELECT #sort:=0) sub2
) sub1
WHERE sub1.userid = 8
Borrowing the idea from: https://stackoverflow.com/a/4474389/92063
SELECT
#rn:=#rn+1 AS RANK
,USER_ID
,POINTS
FROM (
SELECT
R.userid AS USER_ID
,R.points AS POINTS
FROM
rank R
INNER JOIN
settings S
ON R.userid = S.userid
WHERE
S.active = 1
ORDER BY
R.points DESC
) t1, (SELECT #rn:=0) t2;