Special thanks to Hannes Ljungberg for finding multiple implementation
gaps.
Thanks also to Simon Charette, Adam Johnson, and Mariusz Felisiak for
reviews.
Adds support for joint predicates against window annotations through
subquery wrapping while maintaining errors for disjointed filter
attempts.
The "qualify" wording was used to refer to predicates against window
annotations as it's the name of a specialized Snowflake extension to
SQL that is to window functions what HAVING is to aggregates.
While not complete the implementation should cover most of the common
use cases for filtering against window functions without requiring
the complex subquery pushdown and predicate re-aliasing machinery to
deal with disjointed predicates against columns, aggregates, and window
functions.
A complete disjointed filtering implementation should likely be
deferred until proper QUALIFY support lands or the ORM gains a proper
subquery pushdown interface.
The introduction of the Expression.empty_aggregate_value interface
allows the compilation stage to enable the EmptyResultSet optimization
if all the aggregates expressions implement it.
This also removes unnecessary RegrCount/Count.convert_value() methods.
Disabling the empty result set aggregation optimization when it wasn't
appropriate prevented None returned for a Count aggregation value.
Thanks Nick Pope for the review.
This required implementing a limited form of dynamic dispatch to combine
expressions with numerical output. Refs #26355 should eventually provide
a better interface for that.
This patch does not remove all occurrences of the words in question.
Rather, I went through all of the occurrences of the words listed
below, and judged if they a) suggested the reader had some kind of
knowledge/experience, and b) if they added anything of value (including
tone of voice, etc). I left most of the words alone. I looked at the
following words:
- simply/simple
- easy/easier/easiest
- obvious
- just
- merely
- straightforward
- ridiculous
Thanks to Carlton Gibson for guidance on how to approach this issue, and
to Tim Bell for providing the idea. But the enormous lion's share of
thanks go to Adam Johnson for his patient and helpful review.
This allows using expressions that have an output_field that is a
BooleanField to be used directly in a queryset filters, or in the
When() clauses of a Case() expression.
Thanks Josh Smeaton, Tim Graham, Simon Charette, Mariusz Felisiak, and
Adam Johnson for reviews.
Co-Authored-By: NyanKiyoshi <hello@vanille.bid>
