mysql SORT BY amount of unique word matches - mysql

Question

I've found many questions that ask for amount of appearences, but none that ask the very same as I wish to do.
A dynamically generated (prepared-statement) query will result in something like this:
SELECT * FROM products WHERE
( title LIKE ? AND title LIKE ? ) AND
( content LIKE ? OR content LIKE ? ) AND
( subtitle LIKE ? AND author LIKE ? )
ORDER BY relevance LIMIT ?,?
The amount of words entered, (and so the amount of LIKE) are for title,content and author a variable amount (depending on the search query).
Now I've added a ORDER BY relevance. But I wish this order to be the amount of unique words from the content-field that match. (Note: Not on the amount of appearences, but on the amount of entered strings in the content column that have at least one match).
Example table products:
id | title | subtitle | content
------------------------------------
1 | animals | cat | swim swim swim swim swim swim swim
2 | canimal | fish | some content
3 | food | roasted | some content
4 | animal | cat | swim better better swims better something else
5 | animal | cat | dogs swim better
Example query (with prepared statements ? filled in):
SELECT * FROM products WHERE
( title LIKE %animal% ) AND
( content LIKE %dog% OR content LIKE %swim% OR content LIKE %better% ) AND
( subtitle LIKE %cat% )
ORDER BY relevance LIMIT 0,10
Expected results (in correct order!):
id | amount of matches
-----------------
5 | 3 (dog, swim, better)
4 | 2 (swim, better)
1 | 1 (swim)
I have an Innodb table and mysql version lower than 5.6, therefore I can't use MATCH...AGAINST.
I was thinking this could be solved with WHEN CASE ... THEN. But I have no idea how I could create this sorting.

Answer 1

You can do it in many ways for example
ORDER BY SIGN(LOCATE('dog',content))+
SIGN(LOCATE('swim',content))+
SIGN(LOCATE('better',content)) DESC
SQLFiddle demo
or with CASE
ORDER BY
CASE WHEN content LIKE '%dog%'
THEN 1
ELSE 0
END
+
CASE WHEN content LIKE '%swim%'
THEN 1
ELSE 0
END
+
CASE WHEN content LIKE '%better%'
THEN 1
ELSE 0
END
DESC

Answer 2

Check like this.
SELECT id,CONCAT_WS('-',COUNT(LENGTH(content) - LENGTH(REPLACE(content, ' ', '')) + 1),REPLACE(content,' ',',')) AS amount of matches FROM products
WHERE
( title LIKE %animal% ) AND
( content LIKE %dog% OR content LIKE %swim% OR content LIKE %better% ) AND
( subtitle LIKE %cat% )
GROUP BY id
ORDER BY id