One problem I've had in development recently is the inability to get the
aliased name of a table from a query. We're using a PHP framework for
querying, which internally uses pg_field_name to retrieve the select list
field name, which is great. There is alwo pg_table_name, to retrieve the
table the field originated from. The problem is that this returns the name
of the table, unaliased. If a query does a self join, you can't retrieve a
distinguishing table alias name for that field. For example:

SELECT a.mycolumn, b.mycolumn
FROM mytable a, mytable b
WHERE ...

If I controlled query generation at all times, I could simply alias
a.mycolumn and b.mycolumn differently in the select list. But if for
example this is SELECT * FROM, those columns are indistinguishable.

Cheers,
Scott