Method is_empty

src/expr/src/relation.rs:1467–1473

Indicates if this is a constant empty collection. A false value does not mean the collection is known to be non-empty, only that we cannot currently determine that it is statically empty.

(&self)

    /// A false value does not mean the collection is known to be non-empty,
    /// only that we cannot currently determine that it is statically empty.
    pub fn is_empty(&self) -> bool {
        if let Some((Ok(rows), ..)) = self.as_const() {
            rows.is_empty()
        } else {
            false
        }
    }

    /// If the expression is a negated project, return the input and the projection.
    pub fn is_negated_project(&self) -> Option<(&MirRelationExpr, &[usize])> {