min/max of decimal/interval depends on input order

[xiangjinwu]

Describe the bug

Similar to #3873, it is debatable whether the minimum of 1.0 and 1.00 should be the former or latter. Do we also need to output the canonical value from the equivalent class so that it is agnostic of input order?

To Reproduce

create table t (v1 decimal, v2 interval);
create materialized view mv1 as select min(v1) as min1, min(v2) as min2, max(v1) as max1, max(v2) as max2 from t;

insert into t values (1.0, '30 day'), (1.00, '1 month');
select * from mv1;
select min(v1) as min1, min(v2) as min2, max(v1) as max1, max(v2) as max2 from t;

delete from t where v1 = 1;
insert into t values (1.00, '1 month'), (1.0, '30 day');
select * from mv1;
select min(v1) as min1, min(v2) as min2, max(v1) as max1, max(v2) as max2 from t;

Expected behavior

Open to discuss. Possible behaviors:

• First value win / last value win (current and PostgreSQL)
• Canonical value from the equivalent class
• order by

Additional context

No response

[xiangjinwu]

This is just one of the indeterminism sources. No immediate fix needed. Keeping it open for more time so that we can summarize our decision regarding such cases.