MySQL fulltext search over multiple rows

Question

I have a table called essays which has a 1-to-M relationship with a table called paragraphs . Therefore, the paragraphs table has foreign key pointing to essay .

The current problem I have is that, if I make a search, MySQL will look at each individual paragraph, but has no idea that multiple paragraphs can point to the same book.

My fulltext search looks like this:

SELECT DISTINCT *, 
 MATCH(essays.title) AGAINST('my search') as tscore,
 MATCH(paragraphs.content) AGAINST('my search') as cscore
FROM essays 
INNER JOIN paragraphs ON paragraphs.essay_id = essays.id
WHERE 
 MATCH(essays.title) AGAINST('my search')
 OR MATCH(paragraphs.content) AGAINST('my search')
ORDER BY (3 * tscore + cscore) DESC

Is there a way to make MySQL search for something across all the paragraphs of an essay and just return that essay?

Answer 1

Does something like this work for you?

SELECT essays.id, essays.title,
   MATCH(essays.title) AGAINST('my search') as tscore,
   MATCH(paragraphs.content) AGAINST('my search') as cscore
FROM essays 
   INNER JOIN paragraphs ON paragraphs.essay_id = essays.id
GROUP BY essays.id
   HAVING tscore > 0 OR cscore > 0
ORDER BY (3 * tscore + cscore) DESC;

You could also use WHERE clause instead of HAVING, but then you need to:

SELECT essays.id, essays.title,
   MATCH(essays.title) AGAINST('my search') as tscore,
   MATCH(paragraphs.content) AGAINST('my search') as cscore
FROM essays 
   INNER JOIN paragraphs ON paragraphs.essay_id = essays.id
WHERE 
   MATCH(essays.title) AGAINST('my search')
   OR MATCH(paragraphs.content) AGAINST('my search')
GROUP BY essays.id
ORDER BY (3 * tscore + cscore) DESC;

Note that you should not use SELECT * when using GROUP BY because of unwanted aggregation issues that might pop up.