Method contains_outer_reference

datafusion/expr/src/logical_plan/plan.rs:1475–1487

If this node's expressions contains any references to an outer subquery

(&self)

    /// If this node's expressions contains any references to an outer subquery
    pub fn contains_outer_reference(&self) -> bool {
        let mut contains = false;
        self.apply_expressions(|expr| {
            Ok(if expr.contains_outer() {
                contains = true;
                TreeNodeRecursion::Stop
            } else {
                TreeNodeRecursion::Continue
            })
        })
        .unwrap();
        contains
    }

    /// Get the output expressions and their corresponding columns.
    ///