Mysql – Eav model sql select only products with all 3 values

I personally would use a model similar to the following:

The product table would be pretty basic, your main product details:

create table product
(
  part_number int, (PK)
  name varchar(10),
  price int
);
insert into product values
(1, 'product1', 50),
(2, 'product2', 95.99);

Second the attribute table to store the each of the different attributes.

create table attribute
(
  attributeid int, (PK)
  attribute_name varchar(10),
  attribute_value varchar(50)
);
insert into attribute values
(1, 'color', 'red'),
(2, 'color', 'blue'),
(3, 'material', 'chrome'),
(4, 'material', 'plastic'),
(5, 'color', 'yellow'),
(6, 'size', 'x-large');

Finally create the product_attribute table as the JOIN table between each product and its attributes associated with it.

create table product_attribute
(
  part_number int, (FK)
  attributeid int  (FK) 
);
insert into product_attribute values
(1,  1),
(1,  3),
(2,  6),
(2,  2),
(2,  6);

Depending on how you want to use the data you are looking at two joins:

select *
from product p
left join product_attribute t
  on p.part_number = t.part_number
left join attribute a
  on t.attributeid = a.attributeid;

See SQL Fiddle with Demo. This returns data in the format:

PART_NUMBER | NAME       | PRICE | ATTRIBUTEID | ATTRIBUTE_NAME | ATTRIBUTE_VALUE
___________________________________________________________________________
1           | product1   | 50    | 1           | color          | red
1           | product1   | 50    | 3           | material       | chrome
2           | product2   | 96    | 6           | size           | x-large
2           | product2   | 96    | 2           | color          | blue
2           | product2   | 96    | 6           | size           | x-large

But if you want to return the data in a PIVOT format where you have one row with all of the attributes as columns, you can use CASE statements with an aggregate:

SELECT p.part_number,
  p.name,
  p.price,
  MAX(IF(a.ATTRIBUTE_NAME = 'color', a.ATTRIBUTE_VALUE, null)) as color,
  MAX(IF(a.ATTRIBUTE_NAME = 'material', a.ATTRIBUTE_VALUE, null)) as material,
  MAX(IF(a.ATTRIBUTE_NAME = 'size', a.ATTRIBUTE_VALUE, null)) as size
from product p
left join product_attribute t
  on p.part_number = t.part_number
left join attribute a
  on t.attributeid = a.attributeid
group by p.part_number, p.name, p.price;

See SQL Fiddle with Demo. Data is returned in the format:

PART_NUMBER | NAME       | PRICE | COLOR | MATERIAL | SIZE
_________________________________________________________________
1           | product1   | 50    | red   | chrome   | null
2           | product2   | 96    | blue  | null     | x-large

As you case see the data might be in a better format for you, but if you have an unknown number of attributes, it will easily become untenable due to hard-coding attribute names, so in MySQL you can use prepared statements to create dynamic pivots. Your code would be as follows (See SQL Fiddle With Demo):

SET @sql = NULL;
SELECT
  GROUP_CONCAT(DISTINCT
    CONCAT(
      'MAX(IF(a.attribute_name = ''',
      attribute_name,
      ''', a.attribute_value, NULL)) AS ',
      attribute_name
    )
  ) INTO @sql
FROM attribute;

SET @sql = CONCAT('SELECT p.part_number
                    , p.name
                    , ', @sql, ' 
                   from product p
                   left join product_attribute t
                     on p.part_number = t.part_number
                   left join attribute a
                     on t.attributeid = a.attributeid
                   GROUP BY p.part_number
                    , p.name');

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

This generates the same result as the second version with no need to hard-code anything. While there are many ways to model this I think this database design is the most flexible.

First of all, what you are about to design is probably a VERY bad idea. A much better solution would be to have a dynamic schema where you add new tables and have the application understand how to query those table (you could place them in a schema). This largely avoids all the locking and query plan issues you are bound to run into with this model. There is nothing wrong with applications running CREATE TABLE now and again.

Second, I am not sure I understand why you have normalised Parameter into its own table? Why not put that directly into the ManufacturerParameter table.

Third, if you insist on proceeding with your current model, there are ways to achieve what you want (at least if I am interpreting your requirement correctly). What you can do is to write your query in such a way that it is a sums up the search argument when there is a match and then use HAVING to filter out the values that match. I am assuming that only one of the fields Text, Boolean, Datum etc are populated per ProductParameter record (you probably want to enforce this with a constraint)

For example, to search for all products that have a bolean = true for one parameter AND text = 'abc' for some other parameter you can do:

SELECT P.Name
FROM Product P
JOIN ProductParameter PP
WHERE P.ID = Foo
  AND PP.Boolean = 1 OR PP.Text = 'abc'  ... /* For each filter */
GROUP BY P.Name /* And any other things you want out of product */
HAVING COUNT(*) >= [Number of where clauses]

If you need to list all the parameters of this product, you can use the above query template as a nested query and join back to ProductParameter.

The above query CAN be optimised by maintaining a computed column in ProductParameter that has a string representation of the different data types in that table. That way, the above OR statements can be rewritten as an IN list (which you will want to pass as a table valued parameter).

I would like to repeat that what you are doing is probably very wrong. If you do it, you will most likely need to hand tune most of your query plans - the optimiser will not help you anymore. And that is assuming you don't have too many query variants, which will run your plan cache full.