Hello Paulo,
About Harry's scenario, he needs the standard "OR".
For what he told in the other post, he wants to filter his main entity Med... by a search string and return all records that match the search string, even if the other entities conditions are not met.
If you use an AND you will get results only when all conditions are true.
Ex.
He wants all Med... records whose name has "RON" on it, and for those records, he wants to left join all the records on the O... entity if they met the second criteria, like "XYZ", and so on.
I may understood wrong, but this is what we have being discussing there.
In any case, this is really a bug and needs to be addressed.
Thanks!
Cheers,
Eduardo Jauch