multi column analyze

Lets say I have a table like this:
id int, attrib text, value text

And I want to query like this:
SELECT id FROM mytable WHERE attrib = 'favcolor' AND value = 'red';

Suppose there are multiple possible values for attrib, but the value of value will depened
on what attrib is. The breakdown of value based on favcolor might be 20% blue, 30% green,
50% red. Is there any way to make this information available to the analyzer? 50% of the
values might be red when attrib is 'favcolor' but be a miniscule percentage overall.