Mysql Product Filters with Multiple Options

Question

For example, I have a list of TVs, and each TV has attributes such as: Brand (Samsung, Sony, etc.), size (80 cm, 116 cm, etc.), SmartTv (yes, no) .

I have the following diagram:

   CREATE TABLE `products` (
  `id` int(11) NOT NULL auto_increment,
  `name` varchar(150) NOT NULL,
)

CREATE TABLE `attributes` (
  `id` int(11) NOT NULL auto_increment,
  `name` varchar(20) character set latin1 NOT NULL
)

CREATE TABLE `attributes_entity` (
  `product_id` int(11) NOT NULL,
  `attribute_id` int(11) NOT NULL,
  `value_id` int(11) NOT NULL,
)

CREATE TABLE `attributes_values` (
  `id` int(11) NOT NULL auto_increment,
  `value` varchar(255) default NULL,
)

If I want all the TVs from samsung I said like this:

    SELECT
    `p`.`id`,
    `p`.`name`
FROM `attributes_entity` `ae`
    INNER JOIN `products` `p` ON `ae`.`product_id`=`p`.`id`
    INNER JOIN `attributes` `a` ON `ae`.`attribute_id`=`a`.`id`
    INNER JOIN `attributes_values` `av` ON `ae`.`value_id`=`av`.`id`
WHERE (`a`.`name`='samsung' AND `av`.`value`='samsung')

It's great, but what if I want: all Samsung TVs that are smartTv:

     SELECT
    `p`.`id`,
    `p`.`name`
FROM `attributes_entity` `ae`
    INNER JOIN `products` `p` ON `ae`.`product_id`=`p`.`id`
    INNER JOIN `attributes` `a` ON `ae`.`attribute_id`=`a`.`id`
    INNER JOIN `attributes_values` `av` ON `ae`.`value_id`=`av`.`id`
WHERE (`a`.`name`='samsung' AND `av`.`value`='samsung')
//imposible query
and (`a`.`name`='smartv' AND `av`.`value`='yes')

How do I fix a query with multiple identifiers?

Answer 1

The first idea, from my head - try replacing your connections with an internal query and count the number of relevant attributes:

SELECT `p`.`id`, `p`.`name`
FROM   `products` `p`
WHERE   `p`.`id` IN (SELECT     `ae`.`product_id`
                     FROM       `attributes_entity` `ae`
                     INNER JOIN `attributes` `a` ON `ae`.`attribute_id`=`a`.`id`
                     INNER JOIN `attributes_values` `av` ON `ae`.`value_id`=`av`.`id`
                     WHERE       ((`a`.`name`='samsung' AND `av`.`value`='samsung') OR
                                  (`a`.`name`='smartv' AND `av`.`value`='yes'))
                     HAVING COUNT(*) >= 2 -- number of matching attributes required
                    );