I have created a database and website that will be used by football managers to select their team etc. Once a match has been completed events will be stored in the match_players table. Such events are Goal, Yellow Card, Red Card etc. I have no problem getting this information into php from SQL db.
I need to add up how many times a Goal appears (a '1' is placed in the SQL table) and for what team so that a final score can be displayed. So, for example, if Team A has 1 goal and Team B has 2 then I need to display that. I am trying to count the amount of times that a Goal is registered in the table. Any help will be greatly appreciated.
You can use MYSQL SUM
select SUM(Goal) from match_players where Team="A"
Or you can get the same for all teams by
select Team,SUM(Goal) from match_players group by Team
Why don't you demand this sum to SQL directly?
SELECT SUM(goals)
FROM match_table
WHERE team = 'Barcellona'
This should be much faster also than elaborate all data at "php-level"
If you want this detail for all teams
SELECT team,SUM(goals)
FROM match_table
GROUP BY team
Well if you store a 1 each time a goal is scored, your table looks like this:
TeamID goal
1 1
2 1
1 1
3 1
2 1
2 1
1 1
So you just want a count of how many times a team appears in that table:
select TeamID, count(*) from table group by TeamID
Will give you
TeamID | count(*)
1 | 3
2 | 3
3 | 1
Related
I'm working on a track and field ranking database in MySQL/PHP5 whereby I'm struggling to find the best way to query results per unique athlete by highest value.
just
SELECT distinct name, event
FROM results
sample database
name | event | result
--------------------------
athlete 1 | 40 | 7.43
athlete 2 | 40 | 7.66
athlete 1 | 40 | 7.33
athlete 1 | 60 | 9.99
athlete 2 | 60 | 10.55
so let's say that in this case I'd like to rank the athletes on the 40m dash event by best performance I tried
SELECT distinct name, event
FROM results
WHERE event = 40
ORDER by result DESC
but the distinct only leaves the first performance (7.43) of the athlete which isn't the best (7.33). Is there an easy way other than creating a temp table first whereby the results are ordered first and performing a select on the temp table afterwards?
You might be interested in group by:
SELECT name, min(result) as result
FROM results
WHERE event = 40
GROUP BY name
This gives you the best result per athlete.
As suggested by spencer, you can also order the list by appending this:
ORDER BY min(result) ASC
The problem is that the columns used in the ORDER BY aren't specified in the DISTINCT. To do this, you need to use an aggregate function to sort on, and use a GROUP BY to make the DISTINCT work.
SELECT distinct name, event
FROM results
WHERE event = 40
GROUP BY name
ORDER by result DESC
I run a management system where people who work different shifts are registered.
I'd like to be able to make a display of how many times each worker/volunteer worked same shifts, like this:
|Amy|Carl|Max|
|---|----|---|
Amy | X | 2 | 6 |
Carl| 2 | X | 5 |
Max | 6 | 5 | X |
I was hoping you had some ideas how to form the query.
The only idea I've come up with so far is to make PHP create a custom query for each user.
Select count(common between user 1 and 2), count(common between user 1 and ...)
Select count(common between user 2 and 1), count(common between user 2 and ...)
etc..
I consider this an ugly way to do it and I am hoping there is some way of retrieving this data within a single query.
The database is stored like this:
Shifts
ID
From
To
Working
ID
ShiftID
UserID
Users
ID
Name
You'll have to self-join the Working table:
SELECT a.UserID, b.UserID, count(a.ShiftID) AS common_shifts
FROM Working AS a
INNER JOIN Working AS b ON ((a.ShiftID = b.ShiftID) AND (a.UserID <> b.UserID))
HAVING common_shifts > 0
Couldn't you do a cross join where each row is compared to the other, and handle the case of userid=userid to put an X instead?
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.
I was just wondering that, how to get the greatest number in the table.
I mean i have a table called: hits; in that their are 2 columns:
1. id
2. hit
and their are many ids in the table and all have more than 10 hits, now what i want to do is to get the greatest id of the greatest hit
PS: See below:
id | hit
---|----
1 | 10
2 | 15
3 | 45
4 | 9
yes you can use MAX function to use like below
Select Id,Max(hit) from yourtableName group by id having hit=Max(hit)
Select Id,
Max(Hit)
from tableName
group by id
having Max(hit)=(Select Max(Hit) from TableName)
SQL FIDDLE Demo
Wouldn't it be faster to do this:
SELECT * FROM table WHERE 1 ORDER BY hit DESC, id DESC LIMIT 1
Rather than using MAX, Especially if you have a larger table
http://www.witti.ws/blog/2011/04/06/mysqls-max-slow-5-years-later
I'm new to database structure. I'm trying to create an app that allows users to like certain entries, but I want to be able to tie likes to users so that I can change the visuals before/after the like action.
I think from research that I should have an 'entries' and 'users' table and then have a 'likes' table that ties the two to each other.
The only thing I'm unsure of is, when getting and displaying the contents... how would I write the queries? If I query for all the entries I need, do I then go back and individually query each to see if it has a like tied to it for the current user? That seems like it might be a costly operation. Is there a more efficient way?
Hope that makes sense,
Thanks.
I think you have the right database design in mind. As far as queries are concerned, assume tables as such:
Users
ID | Name
1 | Bob
2 | Sally
Entries
ID | Name
1 | Red
2 | Blue
3 | Yellow
Likes
UserID | EntryID
1 | 1
1 | 2
2 | 2
2 | 3
So we can say Bob likes Red and Blue while Sally likes Blue and Yellow. So a query to retrieve all entries, plus an indicator of what Bob likes would be:
SELECT
e.ID,
e.Name,
l.UserID
FROM Entries e LEFT JOIN Likes l ON l.EntryID = e.ID
WHERE l.UserID = 1 -- Bob's User ID
ORDER BY e.Name
This would return
ID | Name | UserID
2 | Blue | 1
1 | Red | NULL
3 | Yellow | 1
The UserID column indicates if Bob likes the entry or not - a NULL is No and a value is Yes.
Assuming you have a table Entries with a column entity_id (and whatever else you store about the entity) and a second table UserLikes that contains the columns user_id and entity_id, you would do the following:
SELECT Entries.col1, Entries.col1 . . ., UserLikes.user_id
FROM Entries LEFT OUTER JOIN UserLikes ON
Entries.entity_id = UserLikes.entity_id
WHERE UserLikes.user_id = :user_id
AND Entity.col_whatever = :whatever
In this example, Entries.col1, Entries.col2 . . . is the list of columns you want to get back about the Entries. The :user_id is a parameter that contains the id of the user you're currently trying to display Entries for. And the last line is standing in for whatever limitations you want to put on the Entries are returned.
This query will give you a row for each Entry you searched for. You can check the value the returned column user_id. If it's NULL then it was not liked by the user, if it contains the user's id, it was liked by the user.
I think u can retrieve the entries and query the likes table at the same time to get if the current user likes the entry performing a stored procedure. So u can control the value of the set of data returned by the query for example returning one colum for the entry text and one boolean column to evaluates the current user likes... In this way you will at least one parameter for the stored procedure to indicate who is the current user
I hope this idea help u...