Could you also support custom, i.e. user-defined aggregate functions?
In the PostgreSQL catalogue "pg_aggregate" there are all available aggregates defined. If I define my own aggregate function FlySpeed SQL Query doesn't look it up there and throws a syntax error, although the aggregate I used in my query is valid.
Is it possible to support user-defined aggregates?
loading of the user-defined aggregate functions for PostgreSql is implemented upstream, and this feature will be included in the next release.