Richard Neill wrote:
> I think that the first query ought to succeed, since although priceband is
> ambiguous (it could mean either tbl_prices.priceband or
> tbl_instruments.priceband), the information in the WHERE clause means that
> they are explicitly equal, and so it doesn't matter which one we use.
Well, it just means the type's equality operator returns true for these
two values -- I'm not sure it is wise to assume they are completely
interchangeable.
More generally, it makes sense to me that resolution of column
references is a property of the syntax of a statement, not something
derived from its semantics (e.g. the fact that we can infer for some
particular statement that two columns are equal).
-Neil