Method outer_schemas_iter

datafusion/sql/src/planner.rs:328–330

Return an iterator of the subquery relations' schemas, innermost relation is returned first. This order corresponds to the order of resolution when looking up column references in subqueries, which start from the innermost relation and then look up the outer relations one by one until a match is found or no more outer relation exist. NOTE this is *REVERSED* order of [`Self::outer_queries_schemas

(&self)

    /// This is useful to resolve the column reference in the subquery by
    /// looking up the outer query schemas one by one.
    pub fn outer_schemas_iter(&self) -> impl Iterator<Item = &DFSchemaRef> {
        self.outer_queries_schemas_stack.iter().rev()
    }

    /// Sets the outer query schema, returning the existing one, if
    /// any