MySQL custom sort by subquery impacts performance - mysql

Question

I have 1 table from which I return search results and display them in a a specific order. This example is an exact, simplified version of my db structure: http://www.java2s.com/Code/SQL/Select-Clause/Orderbyvaluefromsubquery.htm
and here is my current code, which works but heavily impacts performance to a large extend because of the subquery used:
SELECT * FROM `table` AS p1
WHERE CONCAT(title,artist,creator,version) LIKE '%searchInput%'
ORDER BY
(SELECT
MAX(`rating`) FROM `table` AS p2 WHERE p1.setId=p2.setId
) DESC
the above code searches and sorts the result sets by the highest rating in the set and that all rows from the same set are kept together, for example:
id setId rating title,artist,etc...
1 1 5
2 1 5
3 2 7
4 1 6
5 2 1
6 3 3
would sort to:
id setId rating title,artist,etc...
3 2 7
5 2 1
4 1 6
1 1 5
2 1 5
6 3 3
Currently it takes around 8.5sec to query 1000 rows and over half a minute for a large amount of rows, is there any way to improve the performance or would it be better to fetch all the results and sort them in PHP memory?
Help is much appreciated

Answer 1

You can probably speed things up a bit by separating the LIKEs:
SELECT p1.* FROM `table` AS p1
WHERE (title LIKE '%searchInput%')
OR (artist LIKE '%searchInput%')
OR (creator LIKE '%searchInput%')
OR (version LIKE '%searchInput%')
ORDER BY
(SELECT MAX(`rating`) FROM `table` AS p2 WHERE p1.setId=p2.setId) DESC
You could also try to
CREATE INDEX tbl_ndx ON table(setId, rating)
to improve sorting performances.