Hello, I'm reading the docs about the Postgres Rule system here:
https://www.postgresql.org/docs/12/rules-views.html That page says: > It turns out that the planner will collapse this tree into a two-level query > tree: the bottommost SELECT commands will be “pulled up” into the middle > SELECT since there's no need to process them separately. But the middle > SELECT will remain separate from the top, because it contains aggregate > functions. If we pulled those up it would change the behavior of the topmost > SELECT, which we don't want. But I don't see an aggregate function. Is it referring to MIN? But that is this two-param version defined on the same page. It isn't an aggregate: CREATE FUNCTION min(integer, integer) RETURNS integer AS $$ SELECT CASE WHEN $1 < $2 THEN $1 ELSE $2 END $$ LANGUAGE SQL STRICT; Is that an error in the docs, or am I missing something? Does a non-aggregate function also prevent the subqueries from being pulled up? Will all levels of that query actually get combined, or does something else prevent it? Thanks, Paul
