I have a table with:
Id (id of rider)
Time (is the time that he has done)
Session (number session where the time was done)
idlap idRider session time
1 45652 1 4
2 54645 1 2
3 45652 2 2
4 54582 2 1
5 51284 1 3
6 54582 1 3
7 54645 2 4
8 51284 2 5
9 54582 2 2
I wonder how to query in MySQL a result like:
idRider |fast sesion | count laps
45652 | 2 | 1
54645 | 1 | 1
51284 | 3 | 1
54582 | 2 | 2
The query should return in which session the rider got the best time(fast session) and count the number of laps (done in the fast session) grouped by idRider.
Thank you.
This query will give you the results that you want. It JOINs the laps table to the minimum time and number of laps per rider per session, and then to the minimum time per rider to get the fastest session:
SELECT l.idRider, l.session, l.time, s.numlaps
FROM laps l
JOIN (SELECT idRider, `session`, MIN(time) AS fastest, COUNT(*) AS numlaps
FROM laps
GROUP BY idRider, `session`) s ON s.idRider = l.idRider AND s.session = l.session AND s.fastest = l.time
JOIN (SELECT idRider, MIN(time) AS fastest
FROM laps
GROUP BY idRider) f ON f.idRider = s.idRider AND f.fastest = s.fastest
ORDER BY idRider
Output:
idRider session time numlaps
45652 2 2 1
51284 1 3 1
54582 2 1 2
54645 1 2 1
Demo on dbfiddle
Related
I'm looking for some basic direction on how where to start looking to try and rank rows of a common key in a query.
Imagine I have a table like this:
user_id | account_id | score
1 A 10
1 B 20
2 C 10
2 D 20
2 E 30
What I'm hoping to do is add a rank column for relative to each user_id where the highest score gets the top rank:
user_id | account_id | score | rank
1 A 10 2
1 B 20 1
2 C 10 3
2 D 20 2
2 E 30 1
Just looking for some basic direction in terms of which way to head :/
You can use subquery
select
*,
(select count(1)+1 from your_table b where a.user_id=b.user_id and a.score<b.score) as rank
from your_table a
Output
1 A 10 2
1 B 20 1
2 C 10 3
2 D 20 2
2 E 30 1
I need to select user_id & quiz_id, for users which their count of questions in their quiz = sum of correct, this mean they answer 100% correct
answers table:
quiz_id question_id user_id answer_id correct
1 1 1 1 1
1 2 1 6 0
1 3 1 9 1
2 1 2 1 1
2 2 2 5 1
3 4 1 17 1
3 5 1 21 1
3 6 1 25 1
4 1 3 1 1
5 4 4 18 0
6 1 5 1 1
6 2 5 5 1
7 1 3 2 0
7 2 3 7 0
ex 1:
user 1 took "quiz_id" = 1
count of questions in "quiz_id = 1" = 3
sum of correct = 2
so it's not 100%
user_id = 1 in quiz_id = 1 => will not selected
but user_id = 1 will be selected with quiz_id = 3 cause he got 100%
expected results:
quiz_id user_id
2 2
3 1
4 3
6 5
notes:
quiz could be taken with different users with different number of
questions
quiz_id, user_id unique together (user can not take same quiz twice)
thanks,
You should use an aggregate query with HAVING clause:
SELECT quiz_id, user_id
FROM quiz_answer -- or whatever the name is
GROUP BY quiz_id, user_id
HAVING COUNT(question_id) = SUM(correct)
here you must use HAVING instead of WHERE because
The HAVING clause can refer to aggregate functions, which the WHERE
clause cannot
as specified in the docs.
I have two tables, one of a list of competition results, and one with ELO ratings (based on previous competitions).
Fetching the list of competitors for an arbitrary competition is trivial enough, but I also need to get the most recent rating value for them.
score:
id | eventid | competitorid | position
1 1 1 1
2 1 2 2
3 1 3 3
4 2 2 1
5 2 3 2
6 3 1 1
7 3 3 2
8 3 2 3
rating:
id | competitorid | rating
1 1 1600
2 2 1500
3 3 1500
4 2 1600
5 3 1590
Expected output for a query against score.eventid = 3 would be
id | competitorid | position | rating
6 1 1 1600
7 3 2 1590
8 2 3 1600
At the moment my code looks like:
SELECT score.scoreID, score.competitorID, score.position,
rating.id, rating.rating
FROM score, rating
WHERE score.competitorid = rating.competitorid
AND score.eventid = 3
ORDER BY score.position
which gives an output of
id | competitorid | position | rating.id | rating
6 1 1 1 1600
7 3 2 2 1500
7 3 2 4 1590
8 2 3 3 1500
8 2 3 5 1600
basically it's showing the data from the score table for that correct event, but giving me a row for every rating available against that competitorID unfortunately I have no idea where to build in the DISTINCT statement or how to limit it to the most recent result.
MySQL noob, and managed DISTINCT statements, but not with joins. Unfortunately most previous questions seemed to deal with getting distinct results from a single table, which is not quite what I'm after. Thanks!
One way to get the rating is with a correlated subquery:
SELECT s.scoreID, s.eventID, s.competitorID, s.position,
(select r.rating
from rating r
where s.competitorID = r.competitorID
order by r.id desc
limit 1
) as rating
FROM score s
WHERE s.eventID = 3
ORDER BY s.position;
I'm not sure what ratingprid is, so this only includes the rating.
I'll try to explain it as simple as possible:
First some database structure with dummy data.
Structure
tb_spec_fk
feature value
-----------------
1 1
1 2
1 3
1 4
1 5
2 2
2 3
3 1
3 4
4 2
4 3
4 4
5 1
5 3
5 5
6 3
6 5
tb_spec_feature
feature_id filter
------------------
1 2
2 2
3 2
4 2
5 1
6 0
tb_spec_value
value_id name
----------------
1 10
2 20
3 30
4 40
5 50
Now, what I want is the follow result
Result
feature_id min_value max_value
---------------------------------
1 10 50
2 20 30
3 10 40
4 20 40
But how?
Logic
Get from the tb_spec_feature where "filter" equals 2 the highest and lowest values which are present in the tb_spec_value table and connected together trough the tb_spec_fk table.
My attemps
A lot! But I'll spare you :)
SELECT
f.feature_id AS feature_id,
MAX(value.name) AS max_value,
MIN(value.name) AS min_value
FROM tb_spec_feature AS f
JOIN tb_spec_fk AS fk ON f.feature_id=fk.feature
JOIN tb_spec_value AS value ON fk.value=value.id
WHERE f.filter=2
GROUP BY f.feature_id
The two JOIN statements "link" the a feature to a value. GROUP BY groups all rows with the same feature id, and then you can take the min or max or any other aggregate function on those columns.
Demo
Here is how you can do it
select
tsf.feature_id,
tsvl.name as Min_Value,
tsvr.name as Max_Value
from tb_spec_feature as tsf
inner join (select feature , MIN(value) MinV,MAX(value)MaxV from tb_spec_fk group by feature order by feature)as tsfkl on tsfkl.feature = tsf.feature_id
left join tb_spec_value as tsvl on tsvl.value_id = tsfkl.MinV
left join tb_spec_value as tsvr on tsvr.value_id = tsfkl.MaxV
where tsf.filter = 2
group by tsf.feature_id
Output
feature_id | Min_Value | Max_Value
---------------------------------
1 | 10 | 50
2 | 20 | 30
3 | 10 | 40
4 | 20 | 40
Fiddle Demo
I have 4 major tables in my database.
Season --> seasonID
Trials --> trialID
Competition --> CID,name
Camps --> campID,DivisionID(FK)
Divisions ---> DivisionID
Contestants --->ContestantID
Now a contestant belongs to / are members of a divisions.
Then a division belongs to a camp.
All this leads to my Performance table.
PERFORMANCE TABLE
SeasonID|TrialID|CampID|DivID|CompetionID|CtestantID|Score1 |Score2 |Total
1 1 1 1 1 1 20 20 40
1 1 1 1 2 1 20 15 30
1 2 1 1 1 2 10 5 15
1 2 1 1 2 2 5 5 10
1 2 1 1 1 1 10 30 40
1 2 1 1 2 1 20 10 30
How can I query this performance table to give me the competition name, total score and rank (ranking over total score) of each contestant in each competition by trials and by seasons?
Example:
In season 1 and trial 2 I want to have:
SeasonID| TrialID | ContestantID| Competition | TotalScore | Rank
1 2 1 1 40 1
1 2 2 1 15 2
1 2 1 2 30 1
1 2 2 2 10 2
How do I go about this? I have tried table variables, pivot and joins but I can only rank by competitions, but I don't how to aggregate the results to get the result above!
I'm not exactly sure how you calculated your desired results. I think this is what you are after but, if so, the TotalScore in the desired results of your question should be 10 for the last record, not 20.
SELECT SeasonID, TrialID, ContestantID, CompetitionID, Total,
DENSE_RANK() OVER(PARTITION BY CompetitionId ORDER BY Total DESC) AS [Rank]
FROM PerformanceTable