I have a table sorted like this, example;
name | like
_______________
mark 8
luca 8
giorge 2
delta 3
delta 2
luca 8
mark 3
now I would like;
1 merge results name
2 and then sort, after joining the result from largest to smallest, example;
name | like
_______________
luca 16
mark 11
delta 5
giorge 2
how can I do?
simple group by :
select
name, sum(like) as likecount
from tablename
group by name
order by likecount desc
Related
I am trying to get a certain amount of rows of which another amount of rows satisfy a specific condition.
I'll explain.
table 1:
ID | NAME
1 | Thomas
2 | Jason
3 | Oleg
4 | Matt
5 | Sheldon
6 | Jenny
table 2:
ID | ACTIVE
1 | 1
2 | 0
3 | 1
4 | 1
5 | 0
6 | 1
Query:
SELECT tbl_1.ID, tbl_1.NAME, tbl_2.ACTIVE
FROM tbl_1 JOIN tbl_2 ON
tbl_1.ID = tbl_2.ID
WHERE tbl_2.ACTIVE=1
LIMIT 5
in this example I would like to get a minimum number of 5 users, of which 3 are active.
of course the query above will not do the job right, as it limits the total rows to 5. But 3 of the rows in the result (or less if no more exist) MUST be active.
the other way I can think of getting this done, is a union, but my query is so cumbersome, long and complex.
Any ideas?
Use ORDER BY instead:
SELECT tbl_1.ID, tbl_1.NAME, tbl_2.ACTIVE
FROM tbl_1 JOIN
tbl_2
ON tbl_1.ID = tbl_2.ID
ORDER BY (tbl_2.ACTIVE = 1) DESC
LIMIT 5;
This puts the active users at the top of the list and then fills in the rest with other users.
Note: The ORDER BY clause could simply be ORDER BY tbl_2.ACTIVE DESC. I left the boolean logic so you could see the similarity to the WHERE clause.
The way to at least x results is to use the count aggregate and the keyword having
select f1, count(*) records
from yourTable
where whatever
group by f1
having count(*) > x
I have to find a solution for my ranking scenario.
Say i have 100 users in database. And there is 5 subject in another table. In my project users have an option to rate 1 to 5 rating of any subjects. Means a user should have 5 different rating for 5 different subject. I need to shoe on the front page which is the most rated subject on the landing page.
I have a plan like create a table like
table name: user_subject_rate
Structure
id: user_id: subject1: subject2: subject3: subject4: subject5
1 1 3 1 2 5 4
When i create a table like this what happens if a new subject come to rate?
Can anybody suggest me a solution for this? I am using mysql as database.
I would advise you to structure your tables like below.
users
user_id | name
-----------------
1 Michael
2 Andrew
3 Annie
subjects
subject_id | name
----------------------
1 Maths
2 English
3 Physics
4 Chemistry
5 Biology
users_subjects_scores
user_id | subject_id | score
----------------------------
1 1 5
1 2 5
1 3 4
1 4 2
1 5 3
2 1 1
2 2 2
2 3 4
2 4 5
2 5 3
Then you can work out the total score of each subject using this query:
SELECT
name,
COALESCE(SUM(score), 0) AS total_score
FROM
subjects
LEFT JOIN
users_subjects_scores USING (subject_id)
GROUP BY
subject_id
ORDER BY
SUM(score) DESC
Then adding a new subject is as simple as adding a new row to the subjects table.
You can see an SQL fiddle here.
I have a list of films that users can rank in order of which they like best using jQuery UI Sortable (all works well). The lower the order number the better the film (1) and the higher (26) the worse it is. The list of films could be endless but is fixed in the database (users can't add more), so the user can only select from x list of films.
Films do not have to be in the users list, if they haven't seen film 5 then it won't get included (this may be compounding the problem).
Currently this is stored in the table:
film_id | user_id | order
4 2 3
5 3 3
6 2 1
7 2 2
7 3 1
8 3 2
What I want, and don't know where to start is an overall 'Top 10' style list. i.e. film 7 is the most popular because it appears higher up peoples lists and is in more lists. Film 6 could be the most popular but it's only in one list?!
I am stuck on both the logic and the Mysql queries to do it!
I am thinking I might need to weight the order somehow? Or have a separate table with the score per film and just update it after every edit. The following query seems like the right idea if it was just based on the count of items in the table but not when I want to add position in to the equation.
SELECT ff.film_id, COUNT(ff.film_id) AS cnt, SUM(ff.order) AS rank FROM
`favourite_film` AS ff GROUP BY ff.film_id ORDER BY cnt DESC, rank ASC
I guess I need the count of all the films in the table and the sum of the order (but reversed?), my theory then goes flat!
Any help or links would be greatly appreciated. Thanks.
Depending your "business rules", I think you should find some sort of calculation to both take into account the position and the number of "votes".
Just a random guess, but why not sorting by COUNT(votes)/AVG(pos) ? For maintainability reason, you might want to factor out the ranking function:
CREATE FUNCTION ranking(average_pos REAL, vote_count INT)
RETURNS REAL
DETERMINISTIC
RETURN vote_count/average_pos;
The query is now simply:
SELECT film_id,
AVG(pos) as a, COUNT(*) as c, ranking(AVG(pos),COUNT(*)) AS rank
FROM vote GROUP BY film_id
ORDER BY ranking(AVG(pos), COUNT(*)) DESC;
Producing with your example:
+----------+------+----+----------------+
| FILM_ID | A | C | RANK |
+----------+------+----+----------------+
| 7 | 1.5 | 2 | 1.333333333333 |
| 6 | 1 | 1 | 1 |
| 8 | 2 | 1 | 0.5 |
| 5 | 3 | 1 | 0.333333333333 |
| 4 | 3 | 1 | 0.333333333333 |
+----------+------+----+----------------+
See http://sqlfiddle.com/#!2/3b1d9/1
you should have reverted the list before saving it. this way you could leave the unselected movies out of the rating.
a workaround might be:
Count the amount of lists SELECT COUNT(DISTINCT(user_id) save this as $AMOUNT_OF_LISTS
now count the points using
SELECT film_id, (SUM(order)+($AMOUNT_OF_LISTS-COUNT(DISTINCT(user_id)))*POINTS_FOR_NOT_IN_LIST) as points FROM table GROUP BY film_id
logic: sum up all points and add POINTS_FOR_NOT_IN_LIST points for every time not in a list (total amount of lists - amount of times movie is in the list)
insert a value POINTS_FOR_NOT_IN_LIST to your liking. (might be 26 or 27 or even lower)
you probably want to add ORDER BY points DESC LIMIT 10 to the query to get 10 highest points
SELECT MIN( `order` ) , COUNT( * ) AS cnt, `film_id`
FROM `favourite_film`
GROUP BY `film_id`
ORDER BY cnt DESC , `order`
I would do this, I would assign a higher value to the movies with the higher ranking. Then I would sum the values per movie and order by the total descending to get the overall ranking. This way you are giving weight to both the popularity and rankings of each movie.
So if you wanted to do it by the top 3 ranked movies per user you could do this:
SELECT film_id, SUM(3 -- The max number of ranked movies per user
- order -- the ranking
+ 1) total_score
FROM TABLE_NAME
GROUP BY film_id
ORDER BY total_score DESC;
Obviously you could remove the comments
This way the top rated movie would get the higher score, the next highest, the next highest score, etc. If you were counting the top 10 movies per user, just change the 3 to 10.
If i have a MYSQL table that sorts names and one table that sorts value.
Example this is how the table look like:
ID name value
-- ------ -----
1 John 500
2 Rock 350
3 Wayne 700
4 John 350
5 Rock 250
6 Nick 100
7 Sweety 75
8 Lex 350
How do i display the total value for eache user? and also if i want to filter it to only show top 3 is there an easy command for that? Or do i need to make some kind of function.
In PHP
John 850
Wayne 700
Rock 600
Lex 350
Nick 100
Sweety 75
It can be accomplished by the aggregates, kind of
SELECT ID, name, SUM(value) as total_score
FROM user_scores
GROUP BY name
ORDER BY total_score
You need an aggregate function, specifically SUM. You can order a query by any value in the select list, and to go high-to-low just use the DESC keyword:
SELECT Name, SUM(value) AS TotalValue
FROM myTable
GROUP BY Name
ORDER BY TotalValue DESC
The AS TotalValue will ensure that the column name is TotalValue when you reference it in PHP.
I have a problem trying to apply rules about direct matches in a football[soccer] app. I have read this tread and it was very heplful on creating the standing positions table by the points criteria, difference and scored goals.
But i would like to know if is possible to order the teams position by direct matches:
look this positions table:
Pos Team Pld W D L F A GD Pts
1 FC Barcelona 5 2 3 0 8 5 3 9
2 **Inter Milan** 6 2 2 2 11 10 1 8
3 *Real Madrid* 6 2 2 2 8 8 0 8
4 AC Milan 5 0 3 2 8 12 -4 3
As you may see Inter Milan and Real Madrid are tied by points, and the Inter is heading real madrid because its goal difference. The result that i want to get is this :
Pos Team Pld W D L F A GD Pts
1 FC Barcelona 5 2 3 0 8 5 3 9
2 **Real Madrid** 6 2 2 2 8 8 0 8
3 *Inter Milan* 6 2 2 2 11 10 1 8
4 AC Milan 5 0 3 2 8 12 -4 3
Notice that in this time the real madrid is in front the inter milan because it won the two direct matches between them.
i have a table for teams and other for the results.
I would like to achive this using a query in mysql if is possible. Or maybe it would be better if i do this ordering on the server side (PHP).
Thanks any help would be appreciated.
It is impossible to efficiently do what you request in a single query that would return the results you ask for and sort the ties in points with that criteria.
The reasoning is simple: lets assume that you could get a column in your query that would provide or help with the kind of sorting you want. That is to say, it would order teams that are tied in points according to which one has more victories over the others (as this is very likely to happen to more than 2 teams). To make that calculation by hand you would need a double-entry table that shows the amount of matches won between those teams as follows:
| TeamA | TeamB | TeamC
------------------------------
TeamA | 0 | XAB | XAC
TeamB | XBA | 0 | XBC
TeamC | XCA | XCB | 0
So you would just add up each column row and sorting in descending order would provide you the needed data.
The problem is that you don't know which teams are tied before you actually get the data. So creating that column for the general case would mean you need to create the whole table of every team against every team (which is no small task); and then you need to add the logic to the query to only add up the columns of a team against those that are tied with it in points... for which you need the original result set (that you should be creating with the same query anyhow).
It may be possible to get that information in a single query, but it will surely be way too heavy on the DB. You're better off adding that logic in code afterwards getting the data you know you will need (getting the amount of games won by TeamA against TeamB or TeamC is not too complicated). You would still need to be careful about how you build that query and how many you run; after all, during the first few games of a league you will have lots of teams tied up against each other so getting the data will effectively be the same as building the whole double-entry table I used as an example before for all teams against all teams.
create temporary in a stored procedure and call to procedure...
create temporary table tab1 (position int not null auto_increment ,
team_name varchar(200),
points int,
goal_pt int,
primary key(position));
insert into tab1(team_name,
points,
goal_pt)
select team_name,
points,
goal_pt
from team
order by points desc,
goal_pt desc ;