Function strip_outer_reference

datafusion/expr/src/expr_rewriter/mod.rs:205–217

Recursively remove all the ['OuterReferenceColumn'] and return the inside Column in the expression tree.

(expr: Expr)

/// Recursively remove all the ['OuterReferenceColumn'] and return the inside Column
/// in the expression tree.
pub fn strip_outer_reference(expr: Expr) -> Expr {
    expr.transform(|expr| {
        Ok({
            if let Expr::OuterReferenceColumn(_, col) = expr {
                Transformed::yes(Expr::Column(col))
            } else {
                Transformed::no(expr)
            }
        })
    })
    .data()
    .expect("strip_outer_reference is infallible")
}

/// Returns plan with expressions coerced to types compatible with
/// schema types