Right query to limit results in search - php

Question

My db structure is as follows: categories table
+-----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| parent_id | int(11) | NO | | NULL | |
| title | varchar(260) | NO | | NULL | |
| slug | varchar(260) | NO | | NULL | |
| custom | int(11) | NO | | NULL | |
+-----------+--------------+------+-----+---------+----------------+
category_to_content table
+-------------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+---------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| category_id | int(11) | NO | | NULL | |
| content_id | int(11) | NO | | NULL | |
+-------------+---------+------+-----+---------+----------------+
And content table:
+--------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| heading | varchar(200) | NO | | NULL | |
| subheading | text | NO | | NULL | |
| content_text | longtext | NO | | NULL | |
+--------------+--------------+------+-----+---------+----------------+
As you can see, typical adjacency list model in categories table, category_to_content is here because some categories share same content...
There are 4 levels currently, and 'level 0' categories are actually big/main categories (infobases in this case), and i want to limit search JUST to (sub)categories/content which belongs to: current level 0 category (parent_id of level 0 categories is, well.. 0).
I'm using Codeigniter, query builder class (not mandatory, i can use plain sql query, too, if needed), and returned query looks like this:
SELECT `heading`, `slug`
FROM `content`
JOIN `category_to_content` ON `category_to_content`.`content_id` = `content`.`id`
JOIN `categories` ON `categories`.`id`=`category_to_content`.`category_id`
WHERE `categories`.`id` IN('1,2,3') // current level 0 category //subcategories id's, 12,3, just as example...
AND (
`content`.`heading` LIKE '%pod%'
OR `content`.`subheading` LIKE '%pod%'
)
LIMIT 10
However, this doesn't return desired results in all cases. If i remove parentheses from AND portion of query, i got results, BUT from all main categories. With parentheses, no results, in most cases...
E.g. when search term is 'about' i got proper results, when i try with 'podiatry' - no results.
Sample data:
Just to clarify - IN portion works fine, i got proper level 0 subcategories ids on every page.
If you can't see my error (probably something trivial for MySQL gurus), i can send sample data (export from PhPMyAdmin).
EDIT1: Example: When i type 'pod' i would like to get slug from categories table -> 'podiatry', and heading from 'content' table - 'What is podiatry'.
Interesting, when i type 'about' i get desired results (from desired level 0 SUBcategory). DB export - ASAP, so you can test by your self...
EDIT2: link to sample data: http://pastebin.com/YHziZH8f
EDIT3: in this case, i made 3 main/level0 categories (podiatry - cat id=1, infobase2, cat id=208, test3, cat id=213). They all (almost) have some subcategories, and content related to them. If we are on 'podiatry' page - current level 0 category subcategories should be searched. I want to limit search just to these subcategories (current level 0 subcategories). So, if i am on 'podiatry' page, i need 'about' content just for podiatry category (no 'about' from/for the rest of categories).
EDIT4:
Example of successful query:
SELECT `heading`, `slug`
FROM `content`
JOIN `category_to_content` ON `category_to_content`.`content_id` = `content`.`id`
JOIN `categories` ON `categories`.`id`=`category_to_content`.`category_id`
WHERE `categories`.`id` IN('209,210,211,212')
AND (
`content`.`heading` LIKE '%about%'
OR `content`.`subheading` LIKE '%about%'
)
LIMIT 10
I got: heading 'About Infobase2', and 'about-infobase2' slug.
Second search term:
SELECT `heading`, `slug`
FROM `content`
JOIN `category_to_content` ON `category_to_content`.`content_id` = `content`.`id`
JOIN `categories` ON `categories`.`id`=`category_to_content`.`category_id`
WHERE `categories`.`id` IN('209,210,211,212')
AND (
`content`.`heading` LIKE '%categ%'
OR `content`.`subheading` LIKE '%categ%'
)
LIMIT 10
No results. If you test sample data you will see that there is Category 2 (id=210) in categories table, referenced as: category_id 210, content id 48, in category_to_content table, and Category 2 heading in content table (id=48)... What i'm doing wrong... I can't get that data. :(

Answer 1

Try this: first I join all tables needed
SELECT content.heading, categories.slug
FROM content
INNER JOIN category_to_content ctc ON ctc.content_id = content.id
INNER JOIN categories ON categories.id = ctc.category_id
Then we need to keep only "level 1 categories" (direct subcategories of level 0 categories): I used a subquery instead of listing needed ids. It's more dynamic that way: if you add new categories, no need to update the query.
WHERE categories.parent_id IN (SELECT id FROM categories WHERE parent_id = 0)
Finally, search by keyword.
AND (content.heading LIKE '%pod%' OR content.subheading LIKE '%pod%')
(I'm not sure wether you want to add OR categories.slug LIKE '%pod%' in that part of your query or not.)
And you can add LIMIT 10 at the end if needed.
A word about what was wrong in your query, it's this line:
WHERE `categories`.`id` IN('1,2,3')
it should have been IN(1,2,3) or IN('1','2','3') (see the quotes)
"level 1" categories are not only 1, 2 and 3