Function resolve_aliases_to_exprs

datafusion/sql/src/utils.rs:237–252

Rebuilds an `Expr` with columns that refer to aliases replaced by the alias' underlying `Expr`.

(
    expr: Expr,
    aliases: &HashMap<String, Expr>,
)

/// Rebuilds an `Expr` with columns that refer to aliases replaced by the
/// alias' underlying `Expr`.
pub(crate) fn resolve_aliases_to_exprs(
    expr: Expr,
    aliases: &HashMap<String, Expr>,
) -> Result<Expr> {
    expr.transform_up(|nested_expr| match nested_expr {
        Expr::Column(c) if c.relation.is_none() => {
            if let Some(aliased_expr) = aliases.get(&c.name) {
                Ok(Transformed::yes(aliased_expr.clone()))
            } else {
                Ok(Transformed::no(Expr::Column(c)))
            }
        }
        _ => Ok(Transformed::no(nested_expr)),
    })
    .data()
}

/// Given a slice of window expressions sharing the same sort key, find their common partition
/// keys.