I have a MySQL table like this.
| season_id | round_1 | names | score_round_1
| 5 | 10 | John1 | 5
| 5 | 10 | John2 | 3
| 5 | 11 | John3 | 2
| 5 | 11 | John4 | 5
I want to select the records with highest score_round_1 in each round_1(10,11) group .
In this case the first and last rows would be selected.
I tried using the GROUP BY round_1 but that only returns the first row from the two.
Any advice?
Zolka
This is simple
select max(score_round_1),
name
from score
group by round_1
SELECT *
FROM table p1
WHERE score_round_1 = (
SELECT MAX( p2.score_round_1 )
FROM table p2
WHERE p1.round_1 = p2.round_1 ) ANDround_1 !=0
Use aggregate function MAX
SELECT names, MAX(score_round_1) GROUP BY round_1
Related
Having a hard time wrapping my mind around what seems should be a simply query.
So let's say we have a table that keeps track of amount of widgets/balloons in each store by date. How would you get a list of stores and their latest widget/balloons count?
i.e.
mysql> SELECT * FROM inventory;
+----+------------+-------+---------+---------+
| id | invDate | store | widgets | balloons|
+----+------------+-------+---------+---------+
| 1 | 2011-01-01 | 3 | 50 | 35 |
| 2 | 2011-01-04 | 2 | 50 | 35 |
| 3 | 2013-07-04 | 3 | 12 | 78 |
| 4 | 2020-07-04 | 2 | 47 | 18 |
| 5 | 2020-08-06 | 2 | 16 | NULL |
+----+------------+-------+---------+---------+
5 rows in set (0.00 sec)
Would like the result table to list all stores and their latest inventory of widgets/baloons
store, latest widgets, latest balloons
+-------+-----------+---------+
| store | widgets | baloons |
+-------+-----------+---------+
| 2 | 16 | NULL |
| 3 | 12 | 78 |
+-------+-----------+---------+
or grab latest non NULL value for balloons.
This works for all versions of MySQL
select i.*
from inventory i
join
(
select store, max(invDate) as maxDate
from inventory
group by store
) tmp on tmp.store = i.store
and tmp.maxDate = i.invDate
With MySQL 8+ you can do window functions:
with cte as
(
select store, widgets, balloons,
ROW_NUMBER() OVER(PARTITION BY store ORDER BY invDate desc) AS rn
from inventory
)
select * from cte where rn = 1
You can use a correlated sub query to get latest record for each store
select i.*
from inventory i
where i.invDate = (
select max(invDate)
from inventory
where i.store = store
)
order by i.store
DEMO
I need to get AVG for every row in SQL for example:
this is the first table
+ ---+------+-------------+
| course_id | course_name |
+ ----------+-------------+
| 1 | a |
| 2 | b |
| 3 | c |
| 4 | g |
+ ---+------+-------------+
This is the second table
I need to get AVG for both id 1 and 2. the result for example:
+ -------------------+------+----------+
| course_feedback_id | rate |course_id |
+ -================--+------+----------+
| 1 | 4 | 1 |
| 2 | 3 | 1 |
| 3 | 2 | 2 |
+ -------------------+------+----------+
this is the final answer that i need
+ ----------------------+
| course_id | AVG(rate) |
+ -=======--+-----------+
| 1 | 3.5 |
| 2 | 2 |
+ ----------------------+
I tried this soulution but it will give me only the first row not all records.
SELECT *, AVG(`rate`) from secondTable
please help
SELECT `id`, AVG(`rate`) FROM `your_table` GROUP BY `id`
Try this:
SELECT c.course_id, AVG(fb.rate)
FROM course AS c
INNER JOIN course_feedback AS fb ON fb.course_id = c.course_id
GROUP BY c.course_id
Select course_id,t2.rate from table1 where course_id,rate in (Select course_id,avg(rate) as rate from table group by course_id t2)
When you have multiple entries/redundant entries and you want to find some aggregation per each as in this case you got id containing redundant records, In such cases always try to use group by as group by as the name says will group records of the column to which it is applied and if you apply aggregation avg in this case will be groupwise column to which it is being applied not as a whole like for id 1 we have 2 redundant entries so itll apply avg(id1_entries)..likewise as a group.
I'm sorry for fuzzy title of this question.
I have 2 Tables in my database and want to count records of first_table using "group by" on a foreign key id that exists in a column of second_table (which stores ids like array "1,2,3,4,5").
id | name | fk_id
1 | john | 1
2 | mike | 1
3 | jane | 2
4 | tailor | 1
5 | jane | 3
6 | tailor | 5
7 | jane | 4
8 | tailor | 5
9 | jane | 5
10 | tailor | 5
id | name | fk_ids | s_fk_id
1 | xxx | 1,5,6 | 1
2 | yyy | 2,3 | 1
3 | zzz | 9 | 1
4 | www | 7,8 | 1
Now i wrote the following query but it not working properly and displays wrong numbers.
I WANT TO:
1-Count records in first_table group by "fk_id"
2-Sum the counted records which exists in "fk_ids"
3-Display the sum result (sum of related counts) grouped by id.
symbol ' ' means ``.
select sum(if(FIND_IN_SET('fk_id', 'fk_ids')>0,'count',0) 'sum', 'count', 'from'.'fk_id', 'second_table'.* FROM 'second_table'
LEFT JOIN
(
SELECT 'fk_id', count(*) 'count'
FROM 'first_table'
group BY 'fk_id'
) AS 'from'
ON FIND_IN_SET('fk_id', 'fk_ids')>0
WHERE 'second_table'.'s_fk_id'=1
GROUP BY 'id'
ORDER by 'count' DESC
This table has many data and we have no plan to change the structure.
Edit:
Desired output:
id | name | sum
1 | xxx | 7 (3+4+0)
2 | yyy | 2 (1+1)
3 | zzz | 0 (0)
4 | www | 0 (0+0)
After two holidays i came back to work and found out that the "FIND_IN_SET" function is not working properly with space contained string.
And the problem is that i was ignored the spaces too, (same as this question)
Finnaly this query worked:
select sum(`count`) `sum`, `count`, `from`.`fk_id`, `second_table`.* FROM `second_table`
LEFT JOIN
(
SELECT `fk_id`, count(*) `count`
FROM `first_table`
group BY `fk_id`
) AS `from`
ON FIND_IN_SET(`fk_id`, replace(`fk_ids`,' ',''))>0
WHERE `second_table`.`s_fk_id`=1
GROUP BY `id`
ORDER by `count` DESC
And the magic is replace(fk_ids,' ','')
I have a basic table:
+-----+--------+------+------+
| id, | name, | cat, | time |
+-----+--------+------+------+
| 1 | jamie | 1 | 100 |
| 2 | jamie | 2 | 100 |
| 3 | jamie | 1 | 50 |
| 4 | jamie | 2 | 150 |
| 5 | bob | 1 | 100 |
| 6 | tim | 1 | 300 |
| 7 | alice | 4 | 100 |
+-----+--------+------+------+
I tried using the "Left Joining with self, tweaking join conditions and filters" part of this answer: SQL Select only rows with Max Value on a Column but some reason when there are records with a value of 0 it breaks, and it also doesn't return every unique answer for some reason.
When doing the query on this table I'd like to receive the following values:
+-----+--------+------+------+
| id, | name, | cat, | time |
+-----+--------+------+------+
| 1 | jamie | 1 | 100 |
| 4 | jamie | 2 | 150 |
| 5 | bob | 1 | 100 |
| 6 | tim | 1 | 300 |
| 7 | alice | 4 | 100 |
+-----+--------+------+------+
Because they are unique on name and cat and have the highest time value.
The query I adapted from the answer above is:
SELECT a.name, a.cat, a.id, a.time
FROM data A
INNER JOIN (
SELECT name, cat, id, MAX(time) as time
FROM data
WHERE extra_column = 1
GROUP BY name, cat
) b ON a.id = b.id AND a.time = b.time
The issue here is that ID is unique per row you can't get the unique value when getting the max; you have to join on the grouped values instead.
SELECT a.name, a.cat, a.id, a.time
FROM data A
INNER JOIN (
SELECT name, cat, MAX(time) as time
FROM data
WHERE extra_column = 1
GROUP BY name, cat
) b ON A.Cat = B.cat and A.Name = B.Name AND a.time = b.time
Think about it... So what ID is mySQL returning form the Inline view? It could be 1 or 3 and 2 or 4 for jamie. Hows does the engine know to pick the one with the max ID? it is "free to choose any value from each group, so unless they are the same, the values chosen are indeterminate. " it could pick the wrong one resulting in incorrect results. So you can't use it to join on.
https://dev.mysql.com/doc/refman/5.0/en/group-by-handling.html
If you want to use a self join, you could use this query:
SELECT
d1.*
FROM
date d1 LEFT JOIN date d2
ON d1.name=d2.name
AND d1.cat=d2.cat
AND d1.time<d2.time
WHERE
d2.time IS NULL
It is very simple
SELECT MAX(TIME),name,cat FROM table name group by cat
id | userid | total_points_spent
1 | 1 | 10
2 | 2 | 15
3 | 2 | 50
4 | 3 | 5
5 | 1 | 15
With the above table, I would first like to remove duplicates of userid keeping the rows with the largest total_points_spent, like so:
id | userid | total_points_spent
3 | 2 | 50
4 | 3 | 5
5 | 1 | 15
And then I would like to sum the values of total_points_spent, which would be the easy part, resulting in 70.
I am not really sure the "remove" you meant is to delete or to select. Here is the query for select only max totalpointspend record respectively.
SELECT tblA.*
FROM ( SELECT userid, MAX(totalpointspend) AS maxtotal
FROM tblA
GROUP BY userid ) AS dt
INNER JOIN tblA
ON tblA.userid = dt.userid
AND tblA.totalpointspend = dt.maxtotal
ORDER BY tblA.userid