Method filter

src/sql/src/plan/hir.rs:1826–1844

(mut self, mut preds: Vec<HirScalarExpr>)

    }

    pub fn filter(mut self, mut preds: Vec<HirScalarExpr>) -> Self {
        if let HirRelationExpr::Filter {
            input: _,
            predicates,
        } = &mut self
        {
            predicates.extend(preds);
            predicates.sort();
            predicates.dedup();
            self
        } else {
            preds.sort();
            preds.dedup();
            HirRelationExpr::Filter {
                input: Box::new(self),
                predicates: preds,
            }
        }
    }

    pub fn reduce(
        self,