MySQL: Shouldn't this return more rows?

Question

I'm running a simple LIKE search on a table but i can't seem to get more than one result for some reason. In the query example below i include words like "never back down" and "soul surfer" but i only get one of the movies. I have those movies in my database, along with many others.

Here's the query:

SELECT movies . * , GROUP_CONCAT( categories.name ) AS categories, GROUP_CONCAT( categories.id ) AS categories_id
FROM movies
LEFT JOIN movies_categories ON ( movies.id = movies_categories.movie_id ) 
LEFT JOIN categories ON ( movies_categories.category_id = categories.id ) 
WHERE movies.movie_title LIKE  '%surfer%'
OR movies.movie_title LIKE  '%date%'
OR movies.movie_title LIKE  '%never%'
OR movies.movie_title LIKE  '%back%'
OR movies.movie_title LIKE  '%down%'
OR movies.movie_title LIKE  '%surfer%'
OR movies.movie_title LIKE  '%soul%'
OR movies.movie_title LIKE  '%the%'
OR movies.movie_title LIKE  '%transporter%'
LIMIT 0 , 30

I was thinking there must be something wrong with the query, otherwise it would return all results? I am aware some of the words are duplicated in the like clauses, but that shouldn't matter. Have i missed something?

---

Fixed it!

The group_concat() functions i used caused the query to only return one result, and concatenate the categories and category_id's for all movies. I just removed the group_concat()'s and it works now.

Answer 1

You are using GROUP_CONCAT which is an aggregate function and collapses your results into one.

Add a GROUP BY clause:

SELECT movies . * , GROUP_CONCAT( categories.name ) AS categories, GROUP_CONCAT( categories.id ) AS categories_id
FROM movies
LEFT JOIN movies_categories ON ( movies.id = movies_categories.movie_id ) 
LEFT JOIN categories ON ( movies_categories.category_id = categories.id ) 
WHERE movies.movie_title LIKE  '%surfer%'
OR movies.movie_title LIKE  '%date%'
OR movies.movie_title LIKE  '%never%'
OR movies.movie_title LIKE  '%back%'
OR movies.movie_title LIKE  '%down%'
OR movies.movie_title LIKE  '%surfer%'
OR movies.movie_title LIKE  '%soul%'
OR movies.movie_title LIKE  '%the%'
OR movies.movie_title LIKE  '%transporter%'
GROUP BY
        movies.id
LIMIT 0 , 30

Also, if your movies table is MyISAM, you can run this:

SELECT  movies.*,
        GROUP_CONCAT(categories.name) AS categories,
        GROUP_CONCAT(categories.id) AS categories_id
FROM    movies
LEFT JOIN
        movies_categories
ON      movies_categories.movie_id = movies.id
LEFT JOIN
        categories
ON      categories.id = movies_categories.category_id 
WHERE   MATCH(movie_title) AGAINST ("never back down" IN BOOLEAN MODE)
GROUP BY
        movies.id
LIMIT  0, 30

This query will run much faster if you create a FULLTEXT index:

CREATE FULLTEXT INDEX fx_movies_title ON movies (movie_title)