here is my data set and current code: http://sqlfiddle.com/#!2/f9a605/3
| id | courseid | username | day | score |
--------------------------------------------
| 1 | 2 | tim | may 5 | 85 |
| 2 | 2 | mike | may 6 | 86 |
| 3 | 2 | tim | may 7 | 82 |
| 4 | 3 | tim | may 8 | 80 |
| 5 | 2 | mike | may 9 | 79 |
| 6 | 2 | joe | may 10| 81 |
I want to select the values for each user's lowest score where courseid=2 ordered by lowest score so result should look like:
| mike | may 9 | 79 |
| joe | may 10 | 81 |
| tim | may 8 | 82 |
my current code looks like this:
SELECT courseid, username, day, MIN(score) FROM result where courseid = '2' GROUP BY username order by MIN(score) limit 10
my current result looks like this:
| mike | may 6 | 79 |
| joe | may 10 | 81 |
| tim | may 5 | 82 |
The days are wrong.
How do I get the correct day corresponding to the minimum score for that person when courseid =2?
This can be done using a self join on 2 conditions one with username and second with the minimum score
SELECT r.courseid, r.username, r.`day`,r.score
FROM result r
JOIN (SELECT username, MIN(score) score
FROM result
where courseid = '2'
GROUP BY username) r1
ON(r.username = r1.username and r.score = r1.score)
order by r.score
limit 10
Also in your expected result tim should have date of may7
Fiddle Demo
You can use a subquery:
select courseid, username, day, score
from result x
where score = (select min(y.score)
from result y
where y.username = x.username
and x.courseid = y.courseid)
and courseid = 2
order by score
Fiddle:
http://sqlfiddle.com/#!2/f9a605/36/0
Related
I have the following result set...
Name | Team | Score
A | 1 | 10
B | 1 | 11
C | 2 | 9
D | 2 | 15
and I want to add an extra column to the results set for the team score so I can sort on it and end up with the following data set...
Name | Team | Score | TeamScore
D | 2 | 15 | 24
C | 2 | 9 | 24
B | 1 | 11 | 21
A | 1 | 10 | 21
So I end up with the top team first with the members in order.
My actual data is way more complicated than this and pulls in data from several tables but if you can solve this one I can solve my bigger issue!
Join the table to a query that returns the total for each team:
select t.*, s.teamscore
from tablename t
inner join (
select team, sum(score) teamscore
from tablename
group by team
) s on s.team = t.team
order by s.teamscore desc, t.team, t.score desc
See the demo.
Results:
| Name | Team | Score | teamscore |
| ---- | ---- | ----- | --------- |
| D | 2 | 15 | 24 |
| C | 2 | 9 | 24 |
| B | 1 | 11 | 21 |
| A | 1 | 10 | 21 |
In MySQL 8+, we can simplify and just use SUM as an analytic function:
SELECT
Name,
Team,
Score,
SUM(Score) OVER (PARTITION BY Team) AS TeamScore
FROM yourTable
ORDER BY
TeamScore DESC,
Score;
Consider this data:
---+-----------+-------+--+
| id | name | grade | |
+----+-----------+-------+--+
| 13 | Maria | 10 | |
| 18 | Lorenzo | 10 | |
| 2 | Cissa | 10 | |
| 3 | Neto | 9 | |
| 15 | Gabriel | 9 | |
| 10 | Laura | 9 | |
| 12 | Joãozinho | 8 | |
| 16 | Sergio | 8 | |
| 8 | Adriele | 8 | |
| 6 | Jorgito | 8 | |
| 5 | Aline | 8 | |
| 1 | Cintia | 8 | |
| 19 | Fabiana | 7 | |
| 11 | Vinicius | 7 | |
| 9 | Tatiane | 7 | |
| 7 | Chico | 7 | |
| 4 | Marcos | 7 | |
| 14 | Pedro | 6 | |
| 17 | Mauricio | 6 | |
| 20 | Leonardo | 6 | |
+----+-----------+-------+--+
I need the students with the three biggest grades. I think I need to group the data by grade and limit to the top 3 groups.
"SELECT * FROM student GROUP BY grade LIMIT 3" only gives me 3 rows, that's not what I want.
I've tried to use HAVING to filter the groups, but without success. I don't want to set the filter grade>MAX(grade)-2, because theoretically I will not know the grades. But this filter didn't work anyway.
I'am using MySQL. Please help!
You can do this using a join:
select s.*
from student s join
(select grade
from student
group by grade
order by grade desc
limit 3
) g3
on s.grade = g3.grade;
In most databases, you an do this using in:
select s.*
from student s
where s.grade in (select grade
from student
group by grade
order by grade desc
limit 3
);
However, MySQL seems to reject this syntax.
select s1.*
from students s1
join (select distinct grade from students
order by grade desc limit 3) s2 on s1.grade = s2.grade
Alternatively:
select *
from students
where grade >= (select distinct grade from students
order by grade desc limit 2,1)
select s.*
from student s join
(select top 3 grade
from student
group by grade
order by grade desc
) g3
on s.grade = g3.grade;
These are the tables:
professor:
+-------+--------+--------+--------+------+
| empid | name | status | salary | age |
+-------+--------+--------+--------+------+
| 1 | Arun | 1 | 2000 | 23 |
| 2 | Benoy | 0 | 3000 | 25 |
| 3 | Chacko | 1 | 1000 | 36 |
| 4 | Divin | 0 | 5000 | 32 |
| 5 | Edwin | 1 | 2500 | 55 |
| 7 | George | 0 | 1500 | 46 |
+-------+--------+--------+--------+------+
works:
+----------+-------+---------+
| courseid | empid | classid |
+----------+-------+---------+
| 1 | 1 | 10 |
| 2 | 2 | 9 |
| 3 | 3 | 8 |
| 4 | 4 | 10 |
| 5 | 5 | 9 |
| 6 | 1 | 9 |
| 2 | 3 | 10 |
| 2 | 1 | 7 |
+----------+-------+---------+
course:
+----------+------------+--------+
| courseid | coursename | points |
+----------+------------+--------+
| 1 | Maths | 100 |
| 2 | Science | 80 |
| 3 | English | 85 |
| 4 | Social | 90 |
| 5 | Malayalam | 99 |
| 6 | Arts | 40 |
+----------+------------+--------+
The question is :
Return list of employees who have taught course Maths or Science but
not both
The query which I wrote is :
select distinct professor.name from professor
inner join works
on professor.empid=works.empid
where works.courseid in
(select courseid from course where coursename ='Maths' or coursename='Science');
The output I received is:
Arun
Benoy
Chacko
Here the employee 'Arun' shouldnt have been displayed as he as taught both Maths and Science.
Please help me out !!
You may use an aggregate COUNT() to check that the total number of DISTINCT courses taught is exactly 1, while still filtering to the two different types of courses. That ensures that only one, never both, is returned.
Because the IN () limits all rows initially returned only to the two desired courses, professors can have a maximum of 2 possible different courses via COUNT(DISTINCT coursename). A HAVING clause then prohibits those with 2 from the final result set.
SELECT
DISTINCT professor.name
FROM
professor
INNER JOIN works ON professor.empid = works.empid
/* Join against course to get the course names */
INNER JOIN course ON works.courseid = course.courseid
WHERE
/* Restrict only to Maths, Science */
course.coursename IN ('Maths', 'Science')
GROUP BY professor.name
/* Only those with exactly one type of course */
HAVING COUNT(DISTINCT course.coursename) = 1
Here is a demonstration: http://sqlfiddle.com/#!2/2e9610/2
You want to use an xor here instead of an or.
select distinct professor.name from professor
inner join works
on professor.empid=works.empid
where works.courseid in
(select courseid from course where coursename ='Maths' xor coursename='Science');
I found this question which is very similar but I'm still having some troubles.
So I start with table named Scores
id | player | time | scoreA | scoreB |
~~~|~~~~~~~~|~~~~~~|~~~~~~~~|~~~~~~~~|
1 | John | 10 | 70 | 80 |
2 | Bob | 22 | 75 | 85 |
3 | John | 52 | 55 | 75 |
4 | Ted | 39 | 60 | 90 |
5 | John | 35 | 90 | 90 |
6 | Bob | 27 | 65 | 85 |
7 | John | 33 | 60 | 80 |
I would like to select the best average score for each player along with the information from that record. To clarify, best average score would be the highest value for (scoreA + scoreB)/2.
The results would look like this
id | player | time | scoreA | scoreB | avg_score |
~~~|~~~~~~~~|~~~~~~|~~~~~~~~|~~~~~~~~|~~~~~~~~~~~|
5 | John | 35 | 90 | 90 | 90 |
2 | Bob | 22 | 75 | 85 | 80 |
4 | Ted | 39 | 60 | 90 | 75 |
Based on the question I linked to above, I tried a query like this,
SELECT
s.*,
avg_score
FROM
Scores AS s
INNER JOIN (
SELECT
MAX((scoreA + scoreB)/2) AS avg_score,
player,
id
FROM
Scores
GROUP BY
player
) AS avg_s ON s.id = avg_s.id
ORDER BY
avg_score DESC,
s.time ASC
What this actually gives me is,
id | player | time | scoreA | scoreB | avg_score |
~~~|~~~~~~~~|~~~~~~|~~~~~~~~|~~~~~~~~|~~~~~~~~~~~|
1 | John | 10 | 70 | 80 | 90 |
2 | Bob | 22 | 75 | 85 | 80 |
4 | Ted | 39 | 60 | 90 | 75 |
As you can see, it has gotten the correct max avg_score, from record 5, but gets the rest of the information from another record, record 1. What am I missing? How do I ensure that the data all comes from the same record? I'm getting the correct avg_score but I want the rest of the data associated with that record, record 5 in this case.
Thanks in advance!
SELECT x.*
, (scoreA+scoreB)/2 avg_score
FROM scores x
JOIN
( SELECT player, MAX((scoreA+scoreB)/2) max_avg_score FROM scores GROUP BY player) y
ON y.player = x.player
AND y.max_avg_score = (scoreA+x.scoreB)/2;
Try
SELECT s.*,
q.avg_score
FROM scores s JOIN
(
SELECT player,
MAX((scoreA + scoreB)/2) AS avg_score
FROM scores
GROUP BY player
) q ON s.player = q.player
AND (s.scoreA + s.scoreB)/2 = q.avg_score
ORDER BY q.avg_score DESC, s.time ASC
Sample output:
| ID | PLAYER | TIME | SCOREA | SCOREB | AVG_SCORE |
----------------------------------------------------
| 5 | John | 35 | 90 | 90 | 90 |
| 2 | Bob | 22 | 75 | 85 | 80 |
| 4 | Ted | 39 | 60 | 90 | 75 |
Here is SQLFiddle demo
I have events flowing into a MySQL database and I need to group and sum the events to transactions and store away into another table. The data looks like:
+----+---------+------+-------+
| id | transid | code | value |
+----+---------+------+-------+
| 1 | 1 | b | 12 |
| 2 | 1 | i | 23 |
| 3 | 2 | b | 34 |
| 4 | 1 | e | 45 |
| 5 | 3 | b | 56 |
| 6 | 2 | i | 67 |
| 7 | 2 | e | 78 |
| 8 | 3 | i | 89 |
| 9 | 3 | i | 90 |
+----+---------+------+-------+
The events arrive in batches and I would like to create the transaction by summing up the values for each transid, like:
select transid, sum(value) from eventtable group by transid;
but only after all the events for that transid have arrived. That is determined by the event with the code e (b for the beginning, e for the end and i for varying amount of intermediates). Being a novice in SQL, how could I implement the requirement for the existance of the end code before the summing?
Perhaps with having:
select transid, sum(value)
from eventtable
group by transid
having max(case code when 'e' then 1 end)=1;
select transid, sum(value) from eventtable
group by transid
HAVING COUNT(*) = 3
you should count the records in the group. So when there is (b)egin, (i)?? don't know what it is and (e)nd this group is not filtered out.