Function find_out_reference_exprs

datafusion/expr/src/utils.rs:665–669

Collect all deeply nested `Expr::OuterReferenceColumn`. They are returned in order of occurrence (depth first), with duplicates omitted.

(expr: &Expr)

/// Collect all deeply nested `Expr::OuterReferenceColumn`. They are returned in order of occurrence
/// (depth first), with duplicates omitted.
pub fn find_out_reference_exprs(expr: &Expr) -> Vec<Expr> {
    find_exprs_in_expr(expr, &|nested_expr| {
        matches!(nested_expr, Expr::OuterReferenceColumn { .. })
    })
}

/// Search the provided `Expr`'s, and all of their nested `Expr`, for any that
/// pass the provided test. The returned `Expr`'s are deduplicated and returned