Method apply_subqueries

datafusion/expr/src/logical_plan/tree_node.rs:826–842

Similarly to [`Self::apply`], calls `f` on this node and its inputs, including subqueries that may appear in expressions such as `IN (SELECT ...)`.

(
        &self,
        mut f: F,
    )

    /// including subqueries that may appear in expressions such as `IN (SELECT
    /// ...)`.
    pub fn apply_subqueries<F: FnMut(&Self) -> Result<TreeNodeRecursion>>(
        &self,
        mut f: F,
    ) -> Result<TreeNodeRecursion> {
        self.apply_expressions(|expr| {
            expr.apply(|expr| match expr {
                Expr::Exists(Exists { subquery, .. })
                | Expr::InSubquery(InSubquery { subquery, .. })
                | Expr::SetComparison(SetComparison { subquery, .. })
                | Expr::ScalarSubquery(subquery) => {
                    // Wrap in LogicalPlan::Subquery to match f's signature
                    f(&LogicalPlan::Subquery(subquery.clone()))
                }
                _ => Ok(TreeNodeRecursion::Continue),
            })
        })
    }

    /// Similarly to [`Self::map_children`], rewrites all subqueries that may
    /// appear in expressions such as `IN (SELECT ...)` using `f`.