I'm having trouble coming up with a query that returns the player's id, name along with the player's first match date, matchid and opponent.
I want the same information for player's last match as well.
`players`
id | name
1 | playername10
2 | playername22
3 | playername33
4 | playername45
5 | playername55
`matches`
id | gamedate | opponent
1 | 2011-01-01 | opponent1
2 | 2011-01-02 | opponent2
3 | 2011-01-03 | opponent3
4 | 2011-01-04 | opponent4
5 | 2011-01-05 | opponent5
`playermatchscores`
id | matchid | player | goals
1 | 1 | playername10 | 1
2 | 1 | playername22 | 2
3 | 2 | playername10 | 1
4 | 1 | playername33 | 1
5 | 3 | playername45 | 2
6 | 4 | playername55 | 1
7 | 2 | playername55 | 1
8 | 3 | playername22 | 2
9 | 5 | playername55 | 1
Where matchid is a foreign key to the id in table matches.
I tried several queries but I may be approaching it the the wrong way. How can I write a way to get the information I want?
Information about LEFT JOIN: http://www.w3schools.com/sql/sql_join_left.asp
SELECT players.id, MAX(matches.gamedate) AS first_match, MIN(matches.gamedate) AS last_match
FROM playermatchscores
LEFT JOIN players ON players.player = playermatchscores.player
LEFT JOIN matches ON matches.id = playermatchscores.matchid
GROUP BY players.player
I haven't tested this select.
P.S. You should use foreign key for players table too with player_id in playermatchscores.
After the changes in question:
SELECT players.*, matches.*,
FROM playermatchscores
LEFT JOIN players ON players.name = playermatchscores.player
LEFT JOIN matches ON matches.id = playermatchscores.matchid
ORDER BY matches.gamedate ASC
WHERE players.id = 3
LIMIT 1
For the last match replace ASC with DESC.
P.S. This is not the best way to do it but it should work.
Related
It's the 3rd day I'm trying to write a MySQL query. Did lots of search, but it still doesn't work as expected. I'll try to simplify tables as much as possible
System has tkr_restaurants table:
restaurant_id | restaurant_name
1 | AA
2 | BB
3 | CC
Each restaurant has a division assigned (tkr_divisions table):
division_id | restaurant_id | division_name
1 | 1 | AA-1
2 | 1 | AA-2
3 | 2 | BB-1
Then there are meals in tkr_meals_to_restaurants_divisions table, where each meal can be assigned (mapped) to whole restaurant(s) and/or specific division(s). If meal is mapped to restaurant, all restaurant's divisions should see it. If meal is mapped to division(s), only specific division(s) should see it.
meal_id | mapped_restaurant_id | mapped_division_id
1 | 1 | NULL
2 | NULL | 1
3 | NULL | 2
I need to display a list of restaurants and number of meals mapped to it depending on user permissions.
Example 1: if user has permissions to access whole restaurant_id 1 and restaurant_3 (and no specific divisions), then list should be:
AA | 3
CC | 0
(because user can access meals mapped to restaurant 1 + all its division, and restaurant 3 + all its divisions (even if restaurant 3 has no divisions/meals mapped))
Example 2: if user has permissions to access only division_id 1, then list should be:
AA | 1
(because user can only access meals mapped to division 1).
The closest query I could get is:
Example 1:
SELECT *,
(SELECT COUNT(DISTINCT meal_id)
FROM
tkr_meals_to_restaurants_divisions
WHERE
tkr_meals_to_restaurants_divisions.mapped_restaurant_id=tkr_restaurants.restaurant_id
OR tkr_meals_to_restaurants_divisions.mapped_division_id=tkr_divisions.division_id)AS total_meals
FROM
tkr_restaurants
LEFT JOIN
tkr_divisions
ON tkr_restaurants.restaurant_id=tkr_divisions.restaurant_id
WHERE
tkr_restaurants.restaurant_id IN (1, 3)
OR tkr_restaurants.restaurant_id IN (
SELECT restaurant_id
FROM tkr_divisions
WHERE division_id IN (NULL)
)
GROUP BY
tkr_restaurants.restaurant_id
ORDER BY
tkr_restaurants.restaurant_name
However, result was:
AA | 2
CC | 0
I believe I'm greatly over-complicating this query, but all the simpler queries I wrote produced even more inaccurate results.
What about this query:
SELECT
FROM tkr_restaurants AS a
JOIN tkr_divisions AS b
ON a.restaurant_id = b.restaurant_id
LEFT OUTER JOIN tkr_meals_to_restaurants_divisions AS c
ON (c.mapped_restaurant_id = a.restaurant_id OR c.mapped_division_id = b.division_id)
As a Base four your further work. It combine all information into one table. If you add e.g. this:
WHERE a.restaurant_id IN (1, 3)
the result will be
| restaurant_id | restaurant_name | division_id | restaurant_id | division_name | meal_id | mapped_restaurant_id | mapped_division_id |
|---------------|-----------------|-------------|---------------|---------------|---------|----------------------|--------------------|
| 1 | AA | 1 | 1 | AA-1 | 1 | 1 | (null) |
| 1 | AA | 2 | 1 | AA-2 | 1 | 1 | (null) |
| 1 | AA | 1 | 1 | AA-1 | 2 | (null) | 1 |
| 1 | AA | 2 | 1 | AA-2 | 3 | (null) | 2 |
just count the distinct meal ids with COUNT(DISTINCT c.meal_id) and take the restaurant name to get AA: 3 for your example 2
I used a sqlfiddle: http://sqlfiddle.com/#!9/fa2b78/18/0
[EDIT]
Change JOIN tkr_divisions AS b to LEFT OUTER JOIN tkr_divisions AS b
Change SELECT * to SELECT a.restaurant_name, COUNT(DISTINCT c.meal_id)
Add a GROUP BY a.restaurant_name at the end.
Update the SQL Fiddle (new link)
I wanted to learn about web development so I made website with where users can vote on movies, and have issues with making a query for what I need. My tables are as follows:
--rtable--
+-----------+------------+------------+
| movieid | rating | userid |
+-----------+------------+------------+
| 1 | 9 | 27 |
| 2 | 8 | 27 |
| 1 | 10 | 31 |
| 1 | 7 | 42 |
| 2 | 8 | 31 |
+-----------+------------+------------+
--mtable--
+-----------+------------+------------+------------+
| movieid | moviename | movielink | director |
+-----------+------------+------------+------------+
| 1 | Foo | foo.com | bob |
| 2 | Bar | bar.com | steve |
+-----------+------------+------------+------------+
I wanted to make a query to for movie name, movie link, avg(rating), and the users rating (if exists), descending by avg(rating)
--desiredtable (if userid == 42)--
+-----------+------------+------------+------------+
| moviename | movielink | avgrating | yourrating |
+-----------+------------+------------+------------+
| Foo | foo.com | 8.66 | 7 |
| Bar | bar.com | 8 | NULL |
+-----------+------------+------------+------------+
I've managed to get moviename + movielink + avgrating working with OUTER LEFT JOIN but I'm scratching my head as to how to add yourrating. I've tried doubling up on OUTER JOIN and using sub-queries but can't seem to get it to work.
This is what I have so far that works
SELECT mtable.moviename, mtable.movielink, ROUND(AVG(rtable.rating), 2) AS avgrating,
FROM mtable LEFT OUTER JOIN rtable ON rtable.movieid = mtable.movieid GROUP BY mtable.charid ORDER BY AVG(rtable.rating) DESC
You need to join the rtable twice on the mtable, once to get all ratings for the average, once to get the user's rating. You also need to supply the userid for which r2 is filtered within the on clause. That filter criterion in the on clause will apply to r2 only, not the entire dataset.
SELECT mtable.moviename, mtable.movielink, ROUND(AVG(r1.rating), 2) AS avgrating, max(r2.rating) as yourrating
FROM mtable m LEFT OUTER JOIN rtable r1 ON r1.movieid = m.movieid
LEFT JOIN rtable r2 on r2.movieid=m.movieid and r2.userid=...
GROUP BY m.movieid, m.moviename, m.movielink
ORDER BY AVG(r1.rating) DESC
I have SQL (MySQL) that I've can't figure out. The application is using uploaded photos where there are many tagged participants in a photo and there is the possibility to give photos a vote between 1 to 5.
The original query gets all the votes for a photo and orders them by amount of votes and the average of those votes.
Now I need to limit the returned photos by the ones with more than 1 participant. So photos with only 1 participant should not be accounted for.
Simplified schema looks like this.
PHOTOS
----------------------
| id | title |
----------------------
| 1 | Fun stuff |
| 2 | Crazy girls |
| 3 | Single boy |
PHOTO_VOTES
-------------------------------------------
| photo_id | grade | date | user_id |
-------------------------------------------
| 1 | 3 | … | 12 |
| 1 | 3 | … | 12 |
| 2 | 5 | … | 14 |
| 2 | 4 | … | 14 |
| 3 | 4 | … | 15 |
| 3 | 4 | … | 18 |
PHOTO_PARTICIPANTS
-------------------------
| photo_id | user_id |
-------------------------
| 1 | 12 |
| 1 | 21 |
| 1 | 33 |
| 2 | 14 |
| 2 | 33 |
| 3 | 12 |
This is how far I got:
SELECT vote.photo_id,
COUNT(vote.photo_id) AS vote_count,
AVG(vote.grade) AS vote_average,
COUNT(pp.photo_id) AS participant_count
FROM photo_votes vote
LEFT JOIN photos p ON (vote.photo_id = p.id)
LEFT JOIN photo_participants pp ON (pp.photo_id = p.id)
GROUP BY vote.post_id,
HAVING vote_count >= 2
AND vote_average >= 3
AND participant_count > 1
ORDER BY count DESC, average DESC;
Basically what I'm looking for to end up with, excluding the photo with only one participant:
VOTES
-----------------------------------------------------------
| photo_id | vote_count | average | participant_count
-----------------------------------------------------------
| 1 | 2 | 3 | 3
| 2 | 2 | 4.5 | 2
Update
It turned out this is a very inefficient way of trying to do what I want. Gordons answer below did solve the problem, but as soon as I wanted to join fields from the photos table as well, the "cartesian product"-issue became a real problem - it became a very heavy and slow query.
The solution I finally ended up with is adding a cache-field into the photos table keeping track of how many participants are in the photo. In other words I added a 'participant_count' field to 'photos' that is being updated every time a change is made to the participants table. I also run a cron-job regularly to make sure all photos 'participant_count' are properly up-to-date.
First, you don't need left joins for this. But that shouldn't affect the results. The problem is that you have a cartesian product, because you have two 1-n relationships to photos: votes and participants.
The proper way to fix this is by using subqueries:
SELECT pv.photo_id, pv.vote_count, pv.vote_average, pp.participant_count
FROM (SELECT pv.photo_id, count(*) AS vote_count, avg(grade) AS vote_average
FROM photo_votes pv
GROUP BY pv.photo_id
) pv
JOIN
(SELECT pp.photo_id, count(*) AS participant_count
FROM photo_participants p;
GROUP bY pv.photo_id
) pp
ON pv.photo_id = pp.photo_id
WHERE pv.vote_count >= 2 AND
pv.vote_average >= 3 AND
pp.participant_count > 1
ORDER BY pv.vote_count DESC, pv.vote_average DESC;
Note that you don't even need the photos table, because you are not using any fields in it.
I am not the greatest at SQL and I am trying to achieve the following:
I have a table with columns like so:
id | cup_type | cup_id | name
I have a ton of records in the database which will have the same cup_id but different cup_types
I would really like to select records that have the same cup_id but different cup_types
id | cup_type | cup_id | name
1 | TypeOne | 12 | NameOne
2 | TypeTwo | 12 | NameTwo
3 | TypeOne | 13 | NameThree
4 | TypeTwo | 13 | NameFour
5 | TypeOne | 14 | NameFive
6 | TypeOne | 14 | NameSix
When I run the said query it would being me back the following:
id | cup_type | cup_id | name
1 | TypeOne | 12 | NameOne
2 | TypeTwo | 12 | NameTwo
3 | TypeOne | 13 | NameThree
4 | TypeTwo | 13 | NameFour
I hope I have explained this ok and let me know if more clarity is needed.
This query would do the trick
select * from
yourtable a
join (select cup_id, count(distinct cup_type) nbType
from yourTable
group by cup_id) b using(cup_id)
where b.nbType >= 2;
Get a result set from your table where you count the distinct cup_type.
Group that result set by cup_id.
Keep the cup_id so we can join on the same table, using that id.
Return only those where the count of distinct types was at least two.
Try something like this:
select a.id, b.id ....... from t1 as a, t2 as b where a.cup_id=b.cup_id and a.cup_type !=b.cup_type
I have one report page which displays summarized data of other report.I have used php and mysqli. Let me explain you in deep.
I have a web application of store, where you can add product details. Using these product details you can generate packaging list report of products. And based on the generated packaging list report I need to generate one other report which contains summarized data of the packaging list.
below are my tables:
product table:
id | name | desc_id | purity | style_no | type | duty
1 | ABC | 1 | 18 | TEST123 | R | 100
2 | XYZ | 2 | 14 | TEST456 | B | 80
3 | DEF | 1 | 14 | TEST122 | R | 80
4 | PQR | 1 | 18 | TEST124 | R | 120
5 | HJK | 3 | 18 | TEST134 | B | 300
Description table:
id | descrip
1 | Gold Diamond Ring
2 | Gold Diamond Pendant
3 | Gold Diamond Earring
packaging_master table
id | name
1 | pkg_1
2 | pkg_2
packging_details table
id | pkg_id | prod_id
1 | 1 | 1
2 | 1 | 2
3 | 1 | 3
4 | 1 | 4
5 | 1 | 5
I have used below query to generate the packaging list report for specific id, which works correctly.
SELECT id, (SELECT descrip FROM description WHERE id = desc_id ) AS descrip,
style_no, type , purity, duty FROM product WHERE id IN ( SELECT prod_id FROM packaging_list_details WHERE pkg_id =1 ) ORDER BY descrip ASC , purity ASC
which displays below result:
id | descrip | style_no | type | purity | duty
1 |Gold Diamond Ring | TEST123 | R | 18 | 100
4 |Gold Diamond Ring | TEST124 | R | 18 | 120
3 |Gold Diamond Ring | TEST122 | R | 14 | 80
2 |Gold Diamond Pendant| TEST456 | B | 14 | 80
5 |Gold Diamond Earring| TEST134 | B | 18 | 300
Now I want summarized data of above result using query.
Like:
id | descrip | purity | qty | duty
1 |Gold Diamond Ring | 18 | 2 | 220
2 |Gold Diamond Ring | 14 | 1 | 80
3 |Gold Diamond Pendant| 14 | 1 | 80
4 |Gold Diamond Earring| 18 | 1 | 300
How can I achieve this?
You need to use the GROUP_BY statement - See MySql docs for more info.
This will translate the query to such
SELECT d.descrip, p.purity, count(p.purity) as qty, sum(p.duty)
FROM product p
INNER JOIN Description d ON p.desc_id = d.id
LEFT OUTER JOIN packaging_details pg on pg.prod_id = p.id
GROUP BY d.descrip, p.purity
ORDER BY d.descrip desc, p.purity desc
You can also use the sub select methodology you were using, but I prefer using joins. INNER JOIN will link both tables so that all their records are returned. OUTER JOIN will return all rows from the tables on the LEFT of the statement and matches them to values from the tables on the RIGHT.
See a full SQL Fiddle sample.
NOTE: I am not sure where you are getting the values for Id in your sample - Are they simply row numbers?
I think you should rewrite your query using JOINs:
SELECT
P.id
,D.descrip
,P.style_no
,P.type
,P.purity
,P.duty
FROM
packaging_list_details PLD
JOIN
product P ON
(P.id = PLD.prod_id)
LEFT JOIN
description D on
(D.desc_id = P.id)
WHERE
(PLID.pkg_id = 1)
That should give you the same result you already have. To get the totals, you can write a new query, similar to the above:
SELECT
P.id
,D.descrip
,P.type
,P.purity
,COUNT(p.id) as total_products
,SUM(P.duty) as total_duty
FROM
packaging_list_details PLD
JOIN
product P ON
(P.id = PLD.prod_id)
LEFT JOIN
description D on
(D.desc_id = P.id)
WHERE
(PLID.pkg_id = 1)
GROUP BY
P.id
,D.descrip
,P.type
,P.purity
The second query gives you the totals you are looking for.