Function find_agg_expr

datafusion/sql/src/unparser/utils.rs:268–290

(agg: &'a Aggregate, column: &Column)

}

fn find_agg_expr<'a>(agg: &'a Aggregate, column: &Column) -> Result<Option<&'a Expr>> {
    if let Ok(index) = agg.schema.index_of_column(column) {
        if matches!(agg.group_expr.as_slice(), [Expr::GroupingSet(_)]) {
            // For grouping set expr, we must operate by expression list from the grouping set
            let grouping_expr = grouping_set_to_exprlist(agg.group_expr.as_slice())?;
            match index.cmp(&grouping_expr.len()) {
                Ordering::Less => Ok(grouping_expr.into_iter().nth(index)),
                Ordering::Equal => {
                    internal_err!(
                        "Tried to unproject column referring to internal grouping id"
                    )
                }
                Ordering::Greater => {
                    Ok(agg.aggr_expr.get(index - grouping_expr.len() - 1))
                }
            }
        } else {
            Ok(agg.group_expr.iter().chain(agg.aggr_expr.iter()).nth(index))
        }
    } else {
        Ok(None)
    }
}

fn find_window_expr<'a>(
    windows: &'a [&'a Window],