Function extract_step_exprs_and_condition

nodedb-sql/src/planner/cte.rs:227–244

Extract step SELECT expressions and optional WHERE condition as SQL text. Returns `(step_exprs, condition)`.

(expr: &SetExpr)

///
/// Returns `(step_exprs, condition)`.
fn extract_step_exprs_and_condition(expr: &SetExpr) -> Option<(Vec<String>, Option<String>)> {
    let select = match expr {
        SetExpr::Select(s) => s,
        _ => return None,
    };
    let step_exprs = select
        .projection
        .iter()
        .map(|item| match item {
            ast::SelectItem::UnnamedExpr(e) => format!("{e}"),
            ast::SelectItem::ExprWithAlias { expr: e, .. } => format!("{e}"),
            ast::SelectItem::Wildcard(_) => "*".into(),
            ast::SelectItem::QualifiedWildcard(name, _) => format!("{name}.*"),
        })
        .collect();
    let condition = select.selection.as_ref().map(|e| format!("{e}"));
    Some((step_exprs, condition))
}

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