How to perform full text search in MySQL joining multiple tables - mysql

Question

I'm creating e-commerce web site using MySQL. I have successfully created and inserted data to database.
Here is my database schema
table: categories table: product_types
+----+--------------+ +----+-------------+------------+
| id | name | | id | category_id | name |
+----+--------------+ +----+-------------+------------+
| 1 | Electronics | | 1 | 1 | Smartphone |
| 2 | Fashion | | 2 | 1 | Speakers |
+----+--------------+ +----+-------------+------------+
table: products
+----+-----------------+-------------+-------------------+-------+
| id | product_type_id | category_id | name | price |
+----+-----------------+-------------+-------------------+-------+
| 1 | 1 | 1 | Samsung Galaxy A3 | 300 |
| 2 | 1 | 1 | Samsung Galaxy A7 | 400 |
+----+-----------------+-------------+-------------------+-------+
table: options table: option_values
+----+-----------------+-------+ +----+-----------+------------+
| id | product_type_id | name | | id | option_id | name |
+----+-----------------+-------+ +----+-----------+------------+
| 1 | 1 | RAM | | 1 | 1 | 512 MB |
| 2 | 1 | Screen| | 2 | 1 | 1 GB |
| 3 | 1 | OS | | 3 | 3 | Android 5 |
+----+-----------------+-------+ | 4 | 3 | Android 6 |
| 5 | 2 | HD |
| 6 | 2 | FHD |
+----+-----------+------------+
table: product_option_values
+----+------------+-----------+-----------------+
| id | product_id | option_id | option_value_id |
+----+------------+-----------+-----------------+
| 15 | 1 | 1 | 1 |
| 16 | 1 | 2 | 5 |
| 17 | 1 | 3 | 3 |
| 18 | 2 | 1 | 2 |
| 19 | 2 | 2 | 6 |
| 20 | 2 | 3 | 4 |
+----+------------+-----------+-----------------+
Search must trigger through name column of each table and return name and price from products table.
The problem is that I don't know how to perform full text search joining all that tables.
Is there any easy way to do it?

Answer 1

You need a query that LEFT JOINs on each table to search with a condition based on fulltext search function MATCH, with a WHERE clause to filter out non-matching records. The SELECT DISTINCT ensures that you will not see duplicates.
We need to adjust manually the JOIN criteria from each table to products : option_values is the most complicated case as it does not directly references products (an additional join on product_option_values is needed, aliased pov below.
SELECT DISTINCT p.name, p.price
FROM
products p
LEFT JOIN categories c
ON MATCH(c.name) AGAINST('foo' IN NATURAL LANGUAGE MODE)
AND c.id = p.category_id
LEFT JOIN product_types pt
ON MATCH(pt.name) AGAINST('foo' IN NATURAL LANGUAGE MODE)
AND pt.category_id = p.category_id
LEFT JOIN options o
ON MATCH(o.name) AGAINST('foo' IN NATURAL LANGUAGE MODE)
AND o.product_type_id = p.product_type_id
LEFT JOIN product_option_values pov
ON pov.product_id = p.id
LEFT JOIN option_values ov
ON MATCH(ov.name) AGAINST('foo' IN NATURAL LANGUAGE MODE)
AND ov.id = pov.option_value_id
WHERE
COALESCE(c.id, pt.id, o.id, ov.id) IS NOT NULL