straight join on columns with frequency histograms

Dear List,

I'm currently investigating, for a complex issue I have but also "just for fun", the CBO formula used for the estimation of the cardinality of

select ...
  from t1, t2
 where t1.x = t2.x;

where both t1.x and t2.x have *frequency* histograms associated.

Has anyone already investigated something similar, and likes to share the results with me ?

I have already discovered "most" of the formula, that looks simple and intuitive, minus some "border" cases that I'm currently investigating - but I would like to avoid reinventing the wheel if someone has already discovered the full formula.

Thanks in advance
Alberto

-- 
Alberto Dell'Era
"Per aspera ad astra"
--
http://www.freelists.org/webpage/oracle-l