Mysql WHERE not working in table with multiple joins

Question

I am developing a EAV system for multiple entities (Product, Company,...) I will tell the problem at the end.

The database structure is the following:

EAV_ENTITY

This table will give me a list of all available Entities, like:

1 | Product
2 | Company

Structure:

+-------+------------------+------+-----+---------+----------------+
| Field | Type             | Null | Key | Default | Extra          |
+-------+------------------+------+-----+---------+----------------+
| id    | int(11) unsigned | NO   | PRI | NULL    | auto_increment |
| model | varchar(255)     | NO   |     |         |                |
+-------+------------------+------+-----+---------+----------------+

EAV_ATTRIBUTE

This table have a list of attributes, the ref is a mnemonic for getting the attributes by query easier. I add here the entity_type_id that is related with the table eav_entity because I want to limit each attribute to only one entity.

+----------------+------------------+------+-----+---------+----------------+
| Field          | Type             | Null | Key | Default | Extra          |
+----------------+------------------+------+-----+---------+----------------+
| id             | int(11) unsigned | NO   | PRI | NULL    | auto_increment |
| entity_type_id | int(11) unsigned | NO   | MUL | NULL    |                |
| ref            | varchar(50)      | NO   | UNI |         |                |
| name           | varchar(255)     | NO   | UNI |         |                |
+----------------+------------------+------+-----+---------+----------------+

EAV_VALUE

This table have the values related to the attribute, values would be: red, green, orange, for attribute "color"

+-----------------+------------------+------+-----+---------+----------------+
| Field           | Type             | Null | Key | Default | Extra          |
+-----------------+------------------+------+-----+---------+----------------+
| id              | int(11) unsigned | NO   | PRI | NULL    | auto_increment |
| attribute_id    | int(11) unsigned | NO   | MUL | NULL    |                |
| value           | varchar(255)     | NO   | MUL | NULL    |                |
+-----------------+------------------+------+-----+---------+----------------+

EAV_ATTRIBUTE_VALUE

+----------------+------------------+------+-----+---------+----------------+
| Field          | Type             | Null | Key | Default | Extra          |
+----------------+------------------+------+-----+---------+----------------+
| id             | int(11) unsigned | NO   | PRI | NULL    | auto_increment |
| entity_id      | int(11) unsigned | YES  |     | NULL    |                |
| entity_type_id | int(11) unsigned | YES  | MUL | NULL    |                |
| value_id       | int(11)          | YES  |     | NULL    |                |
+----------------+------------------+------+-----+---------+----------------+

Here I make all the "magic", I make a query making a relation between an entity(type, id) and all the values related and the attribute that the value belongs to.

My query is this one

SELECT
    e.model,
    av.entity_id,
    a.id as category_id,
    a.ref as category_ref,
    v.id as value_id

FROM eav_entity as e

RIGHT JOIN eav_attribute_value as av
ON e.id = av.entity_type_id

LEFT JOIN eav_value as v
ON v.id = av.value_id

LEFT JOIN eav_attribute as a
ON v.attribute_id = a.id

WHERE e.model = 'App\Product'

PROBLEM & QUESTION

When I add the statement WHERE e.model ='Whatever' I dont get any result. And it is supposed to be filter. But without the WHERE statement I get the results as expected. I think that it might be a problem related to the way I am doing the joins.

A real example without WHERE e.model

+-------------+-----------+-------------+---------------------------+----------+
| model       | entity_id | category_id | category_ref              | value_id |
+-------------+-----------+-------------+---------------------------+----------+
| App\Product |        13 |           2 | product_development_phase |        2 |
| App\Product |        13 |           2 | product_development_phase |        3 |
| App\Product |        13 |           4 | product_therapeutics      |       58 |
| App\Company |        13 |           4 | product_therapeutics      |       58 |
+-------------+-----------+-------------+---------------------------+----------+

Answer 1

AS @Uuerdo said, I need to add a second backslash as escape character to interpret the second one as a real backslash.

The query will result in the next below:

SELECT
    e.model,
    av.entity_id,
    a.id as category_id,
    a.ref as category_ref,
    v.id as value_id

FROM eav_entity as e

RIGHT JOIN eav_attribute_value as av
    ON e.id = av.entity_type_id

LEFT JOIN eav_value as v
    ON v.id = av.value_id

LEFT JOIN eav_attribute as a
    ON v.attribute_id = a.id

WHERE e.model = "App\\Product"