如何选择列中前5个最频繁的值

Question

I want to select the top 5 most frequent albums from a database, using this database: http://www.sqlitetutorial.net/tryit/query/sqlite-inner-join/#3

with this query:

SELECT
  albums.title AS Album,
  artists.name AS Artist,
  COUNT(albums.title ) as TitleCount
FROM tracks
INNER JOIN albums ON albums.albumid = tracks.albumid
INNER JOIN artists ON artists.artistid = albums.artistid
GROUP BY 
  albums.albumid 
ORDER BY 
  TitleCount DESC

Limit 5 is not a good solution, as in my case, there are 2 albums with 25 titles, what I want is the top 5 by titleCount value. It seems like limit doesn't take COUNT, but integers

expected result:

|Album               |Artist       |TitleCount|
|Greatest Hits       |Lenny Kravitz|57        |  
|Minha Historia      |Chico Buarque|34        |
|Unplugged           |Eric Clapton |30        |
|Lost, Season 3      |Lost         |26        |
|Lost, Season 1      |Lost         |25        |
|The Office, Season 3|The Office   |25        |

ps: this might be a duplicate of SQL - Most frequent value in column of joined tables , but I can't apply it to mine

Answer 1

MySQL's and SQLite's LIMIT clauses both lack a WITH TIES option, which is what you'd need here. So use a subquery instead: Select the five greatest numbers of tracks (which is a rare case where you actually combine GROUP BY with DISTINCT - GROUP BY to get counts per album, DISTINCT to get the five highes different counts), then select the albums having as many tracks. As this is about an aggregation result, this belongs in the HAVING clause:

SELECT
  albums.title AS Album,
  artists.name AS Artist,
  COUNT(*) as TitleCount
FROM tracks
INNER JOIN albums ON albums.albumid = tracks.albumid
INNER JOIN artists ON artists.artistid = albums.artistid
GROUP BY albums.albumid 
HAVING COUNT(*) IN
(
  SELECT DISTINCT COUNT(*)
  FROM tracks
  GROUP BY albumid
  ORDER BY count(*) DESC
  LIMIT 5
)
ORDER BY TitleCount DESC;

Answer 2

Use below code

    SELECT
  albums.title AS Album,
  artists.name AS Artist,
  COUNT(*) as TitleCount
FROM tracks
INNER JOIN albums ON albums.albumid = tracks.albumid
INNER JOIN artists ON artists.artistid = albums.artistid
GROUP BY albums.albumid 
HAVING COUNT(*) IN
(
  SELECT DISTINCT COUNT(*)
  FROM tracks
  GROUP BY albumid
  ORDER BY count(*) DESC

)
ORDER BY TitleCount DESC LIMIT 5;

Answer 3

While the other answer works fine, if you're using sqlite 3.25 or newer (Or I think MySQL 8), this can be done in a simpler fashion using the dense_rank() window function :

WITH rankings(Album, Artist, TitleCount, ranking) AS (
  SELECT al.title, ar.name, count(al.title)
       , dense_rank() OVER (ORDER BY count(al.title) DESC)
  FROM tracks AS t
  INNER JOIN albums AS al ON al.albumid = t.albumid
  INNER JOIN artists AS ar ON ar.artistid = al.artistid
  GROUP BY al.albumid)
SELECT Album, Artist, TitleCount
FROM rankings
WHERE ranking <= 5
ORDER BY ranking;