I have the following query. What results is two coloums, oakid and max(count(rating)). What I want is to have two columns, but instead of actually having the max(count(rating)), I want the rating associated with the max(count(rating)). How can I modify my query to give me this?
select oakid,
(select max(count(rating))
from climbs, routes
where climbs.routename = routes.name
and climbs.climberid = oakid group by routes.rating)
as skill
from climbers;
For example, if I have ratings "hard, hard, easy, easy, easy, medium", the max(count(rating)) will show "3", since there are 3 "easy" ratings, but I want it to show "easy", not "3".
It sounds as though you want the statistical mode (most frequently occurring) rating for each oakid or climberid. Oracle has a handy function to do this for us called STATS_MODE:
SELECT c.climberid AS oakid, STATS_MODE(r.rating) AS skill
FROM climbs c
INNER JOIN routes r ON (c.routename = r.name)
GROUP BY c.climberid;
try the following:
select oakid,
(select rating
from climbs, routes
where climbs.routename = routes.name
and climbs.climberid = oakid
group by routes.rating
having max(count(rating)) = count(rating))
as skill
from climbers
Related
I have a table "Bed" and a table "Component". Between those two I have a m:n relation and the table "BedComponent", where I store the Bed-ID and the Component-ID.
Every Component has a price. And now I want to write a select-statement that gives me the sum of prices for a certain bed.
This is what I have:
SELECT Bed.idBed, Bed.name, SUM(src.price) AS summe, Bed.idCustomer
FROM Bed,
(SELECT price
FROM dbo.Component AS C
WHERE (C.idComponent IN
(SELECT idComponent
FROM dbo.BedComponent AS BC
WHERE 1 = BC.idBed))) AS src
GROUP BY dbo.Bed.idBed, dbo.Bed.name, dbo.Bed.idCustomer;
This statement works. But of course I don't want to write the bed-ID hard coded into my select as it will always calculate the price for bed 1. Instead of the "1" i want to have the current bed-id.
I work with MS SQL Server
Thanks for your help.
I think you want:
select b.idBed, b.name, SUM(src.price) AS summe, b.idCustomer
from bed b join
bedcomponent bc
on b.idBed = bc.idBed join
component c
on c.idComponent = bc.idComponent
group by b.idBed, b.name, b.idCustomer;
The idCustomer looks strange to me in the select and group by, but I don't know what you are trying to achieve.
Also note the use of table aliases, which make the query easier to write and to read.
I am incapable of make a query that return me a results as follows:
TABLES: series, usuarios, siguiendo, valoraciones_personales
Each table has got this records:
example: field1(value), field2(value),...
series (I refer a tv show, I am spanish and here we say "serie=tv_show")
1. id_serie(1),id_titulo('Sons of anarchy')
2. id_serie(2),id_titulo('Lost')
usuarios (user)
1. id_usuario(1), nick('david')
siguiendo (a usser follow a series)
1. id_serie(1),id_usuario(1)
2. id_serie(2),id_usuario(1)
valoraciones_personales (personal assessments)
1. id_serie(1),id_usuario(1),nota(8)
Ok, what I want is a result with all records of the table siguiendo, and if that user valued one of that series, it must shows the score (nota in spanish), and if that user didn´t scored that series, I want to show "without score".
The view I want:
*titulo, nota*
- Sons of anarchy, 8
- Lost, without score
Can anyone help me?
Specifically in MSACCESS
Create a query called something like AllUserSeries
SELECT
U.UserID
,U.FullName
,S.SeriesID
,S.SeriesName
FROM
usuarios as U
,series as S
This is the equivalent of a cross join
Then another:
SELECT
A.FullName
,A.SeriesName
,Nz(Cstr(R.Score),"Not Rated") as Rating
FROM
AllUserSeries AS A
LEFT OUTER JOIN valoraciones_personales AS R
ON A.UserID = R.UserID
AND A.SeriesID = R.SeriesID
WHERE
A.UserID = #UserID
The tricky bit is getting a list of all the series a user may have liked. to do this normally i would do a cross join to get all permutations that could exist, then left join from there to the ratings table using Nz to handle null values as you see fit.
*sorry for kinda making up the other column names it was easier for me to use English hope that okay :D
I've got the code below which displays the location_id and total number of antisocial crimes but I would like to get the location_name from a different table called location_dim be output as well. I tried to find a way to UNION it but couldn't get it to work. Any ideas?
SELECT fk5_location_id , COUNT(fk3_crime_id) as TOTAL_ANTISOCIAL_CRIMES
from CRIME_FACT
WHERE fk1_time_id = 3 AND fk3_crime_id = 1
GROUP BY fk5_location_id;
You want to use join to lookup the location name. The query would probably look like this:
SELECT ld.location_name, COUNT(cf.fk3_crime_id) as TOTAL_ANTISOCIAL_CRIMES
from CRIME_FACT cf join
LOCATION_DIM ld
on cf.fk5_location_id = ld.location_id
WHERE cf.fk1_time_id = 3 AND cf.fk3_crime_id = 1
GROUP BY ld.location_name;
You need to put in the right column names for ld.location_name and ld.location_id.
you need to find a relationship between the two tables to link a location to crime. that way you could use a "join" and select the fields from each table you are interested in.
I suggest taking a step back and reading up on the fundamentals of relational databases. There are many good books out there which is the perfect place to start.
I have this query using PostgreSQL 9.1 (9.2 as soon as our hosting platform upgrades):
SELECT
media_files.album,
media_files.artist,
ARRAY_AGG (media_files. ID) AS media_file_ids
FROM
media_files
INNER JOIN playlist_media_files ON media_files.id = playlist_media_files.media_file_id
WHERE
playlist_media_files.playlist_id = 1
GROUP BY
media_files.album,
media_files.artist
ORDER BY
media_files.album ASC
and it's working fine, the goal was to extract album/artist combinations and in the result set have an array of media files ids for that particular combo.
The problem is that I have another column in media files, which is artwork.
artwork is unique for each media file (even in the same album) but in the result set I need to return just the first of the set.
So, for an album that has 10 media files, I also have 10 corresponding artworks, but I would like just to return the first (or a random picked one for that collection).
Is that possible to do with only SQL/Window Functions (first_value over..)?
Yes, it's possible. First, let's tweak your query by adding alias and explicit column qualifiers so it's clear what comes from where - assuming I've guessed correctly, since I can't be sure without table definitions:
SELECT
mf.album,
mf.artist,
ARRAY_AGG (mf.id) AS media_file_ids
FROM
"media_files" mf
INNER JOIN "playlist_media_files" pmf ON mf.id = pmf.media_file_id
WHERE
pmf.playlist_id = 1
GROUP BY
mf.album,
mf.artist
ORDER BY
mf.album ASC
Now you can either use a subquery in the SELECT list or maybe use DISTINCT ON, though it looks like any solution based on DISTINCT ON will be so convoluted as not to be worth it.
What you really want is something like an pick_arbitrary_value_agg aggregate that just picks the first value it sees and throws the rest away. There is no such aggregate and it isn't really worth implementing it for the job. You could use min(artwork) or max(artwork) and you may find that this actually performs better than the later solutions.
To use a subquery, leave the ORDER BY as it is and add the following as an extra column in your SELECT list:
(SELECT mf2.artwork
FROM media_files mf2
WHERE mf2.artist = mf.artist
AND mf2.album = mf.album
LIMIT 1) AS picked_artwork
You can at a performance cost randomize the selected artwork by adding ORDER BY random() before the LIMIT 1 above.
Alternately, here's a quick and dirty way to implement selection of a random row in-line:
(array_agg(artwork))[width_bucket(random(),0,1,count(artwork)::integer)]
Since there's no sample data I can't test these modifications. Let me know if there's an issue.
"First" pick
Wouldn't it be simpler / cheaper to just use min():
SELECT m.album
,m.artist
,array_agg(m.id) AS media_file_ids
,min(m.artwork) AS artwork
FROM playlist_media_files p
JOIN media_files m ON m.id = p.media_file_id
WHERE p.playlist_id = 1
GROUP BY m.album, m.artist
ORDER BY m.album, m.artist;
Abitrary / random pick
If you are looking for a random selection, #Craig already provided a solution with truly random picks.
You could also use a CTE to avoid additional scans on the (possibly big) base table and then run two separate (cheap) subqueries on the small result set.
For arbitrary selection - not truly random, the result will depend on the physical order of rows in the table and implementation-specifics:
WITH x AS (
SELECT m.album, m.artist, m.id, m.artwork
FROM playlist_media_files p
JOIN media_files m ON m.id = p.media_file_id
)
SELECT a.album, a.artist, a.media_file_ids, b.artwork
FROM (
SELECT album, artist, array_agg(id) AS media_file_ids
FROM x
) a
JOIN (
SELECT DISTINCT ON (1,2) album, artist, artwork
FROM x
) b USING (album, artist);
For truly random results, you can add an ORDER BY .. random() like this to subquery b:
JOIN (
SELECT DISTINCT ON (1, 2) album, artist, artwork
FROM x
ORDER BY 1, 2, random()
) b USING (album, artist);
I have a PHP page running in postgres. I have 3 tables - workorders, wo_parts and part2vendor. I am trying to multiply 2 table column row datas together, ie wo_parts has a field called qty and part2vendor has a field called cost. These 2 are joined by wo_parts.pn and part2vendor.pn. I have created a query like this:
$scoreCostQuery = "SELECT SUM(part2vendor.cost*wo_parts.qty) as total_score
FROM part2vendor
INNER JOIN wo_parts
ON (wo_parts.pn=part2vendor.pn)
WHERE workorder=$workorder";
But if I add the costs of the parts multiplied by the qauntities supplied, it adds to a different number than what the script is doing. Help....I am new to this but if someone can show me in SQL I can modify it for postgres. Thanks
Without seeing example data, there's no way for us to know why you're query totals are coming out differently that when you do the math by hand. It could be a bad join, so you are getting more/less records than you expected. It's also possible that your calculations are off. Pick an example with the smallest number of associated records & compare.
My suggestion is to add a GROUP BY to the query:
SELECT SUM(p.cost * wp.qty) as total_score
FROM part2vendor p
JOIN wo_parts wp ON wp.pn = p.pn
WHERE workorder = $workorder
GROUP BY workorder
FYI: MySQL was designed to allow flexibility in the GROUP BY, while no other db I've used does - it's a source of numerous questions on SO "why does this work in MySQL when it doesn't work on db x...".
To Check that your Quantities are correct:
SELECT wp.qty,
p.cost
FROM WO_PARTS wp
JOIN PART2VENDOR p ON p.pn = wp.pn
WHERE p.workorder = $workorder
Check that the numbers are correct for a given order.
You could try a sub-query instead.
(Note, I don't have a Postgres installation to test this on so consider this more like pseudo code than a working example... It does work in MySQL tho)
SELECT
SUM(p.`score`) AS 'total_score'
FROM part2vendor AS p2v
INNER JOIN (
SELECT pn, cost * qty AS `score`
FROM wo_parts
) AS p
ON p.pn = p2v.pn
WHERE p2n.workorder=$workorder"
In the question, you say the cost column is in part2vendor, but in the query you reference wo_parts.cost. If the wo_parts table has its own cost column, that's the source of the problem.