Linear regression functions aren't implemented correctly #7064
Description
Many of our integration tests seem to fail when we upgrade our own emulation of linear regression functions to Firebird 4.0.0's native support.
Try this, for example:
select regr_avgx(a, b)
from (
select 1, 1 from RDB$DATABASE union all
select 2, 1 from RDB$DATABASE union all
select 3, 2 from RDB$DATABASE union all
select 4, 2 from RDB$DATABASE
) t (a, b);Firebird 4.0 produces the value 4, when it should produce 1.5 like these database products:
Maybe, this gives you a hint about the bug?
select regr_avgx(a, b), regr_avgx(cast(a as bigint), cast(b as bigint))
from (
select 1, 1 from RDB$DATABASE union all
select 2, 1 from RDB$DATABASE union all
select 3, 2 from RDB$DATABASE union all
select 4, 2 from RDB$DATABASE
) t (a, b);
select regr_avgx(cast(a as bigint), cast(b as bigint)), regr_avgx(a, b)
from (
select 1, 1 from RDB$DATABASE union all
select 2, 1 from RDB$DATABASE union all
select 3, 2 from RDB$DATABASE union all
select 4, 2 from RDB$DATABASE
) t (a, b);In both cases, I'm getting this, now:
|REGR_AVGX|REGR_AVGX|
|---------|---------|
|4.0 |0 |