Make custom aggregate function easier to use (accept more input types without creating variants)

Recently I wrote a custom aggregate function in postgres that would return a specific column for the row that matches the max/min aggregate using a different column. While the code in itself works great it is somewhat bothersome to create custom data type for every possible input combination that I might need. Here is the code I use CREATE TYPE agg_tuple_text AS ( exists boolean, value numeric, text text ); -------------------------------------------------------------------------------- CREATE FUNCTION valued_min(old_tuple agg_tuple_text, new_value numeric, new_text text) RETURNS agg_tuple_text LANGUAGE plpgsql AS $$ BEGIN IF (old_tuple).exists = false THEN RETURN (true, new_value, new_text); ELSIF (old_tuple).value > new_value THEN RETURN (true, new_value, new_text); ELSE RETURN old_tuple; END IF; END; $$; -------------------------------------------------------------------------------- CREATE FUNCTION unpack_agg_tuple_text(value agg_tuple_text) RETURNS text LANGUAGE plpgsql AS $$ BEGIN IF (value).exists = false THEN RETURN NULL; ELSE RETURN (value).text; END IF; END $$; -------------------------------------------------------------------------------- CREATE AGGREGATE valued_min(numeric, text) ( INITCOND = '(false, 0, null)', STYPE = agg_tuple_text, SFUNC = valued_min, FINALFUNC = unpack_agg_tuple_text ); -------------------------------------------------------------------------------- -- Example SELECT min(value) as min_value, valued_min(value, name) as min_name, max..., avg... FROM kv; -- Output: -- min_value | min_name | ... -- ----------+--------------------+---- -- 11.11 | this is the lowest | ... EDIT: My goal is drawing a min/max/avg chart for a TSDB and displaying the name of the min and max entries each. Is there a way to achieve this without creating all of these for every possible combination? (Maybe some kind of generic parameter that are present in Java or alike) * Value column types * Various Date/Time types * Numeric types * Maybe text * (any comparable type) * data column types * anytype It would be sufficient if I only could use it for the data value since it isn't used in any calculation inside that code. Unfortunately the anyelement type isn't allowed in custom data types. I already considered using the json type as input, but that feels somewhat wrong, because it looses the type information (especially for date/time types). ------------------------ I use Postgres 10 without extensions, but if this is possible using postgres 1x or using a special extension I'm willing to try. ----------------------- I also considered joining the values, but then I get isues with performance and potential duplicates/rows that have the same value.