Ruby on Rails

Hello. Would somebody like to answer me on question or give some advice?

In my situation I have to use EAV-model (MySQL database) to deal with dynamic attributes (for products: color, weight, height and etc.)
Model: Product, Option, Value

So, in this case I have relation: product has many options through values.
It's okay, when I modify and print it.

But what is the best solution for search on them?
Because I have to have many inner joins with the same table - values
And each join should have own conditions, for example:

    option_alias1.name = 'color' AND values_alias1.value = '100'
    AND option_alias2.name = 'weight' AND values_alias2.value < '200'

So, I can't do it by join existing relation many times, because I haven't got access to aliases. Should I write raw sql queries or there is more convenient way?

Thank you.