Say, I have a table with an index on `(field1,field2,field3)` . I execute a query with `WHERE field2 = A AND field3 = B` . MySQL won't use the mentioned key in this case. So, question is: is there an RDBMS that WOULD use this index? I mean - use it effectively?

PS Please, do not tell me to add an extra key to a table. I just want to know an RDBMS that supports the mentioned feature, if any.

Thanks in advance.