Function extract_col_ref

nodedb-sql/src/planner/join/constraint.rs:127–142

(expr: &ast::Expr)

}

fn extract_col_ref(expr: &ast::Expr) -> Option<String> {
    match expr {
        ast::Expr::Identifier(ident) => Some(normalize_ident(ident)),
        // Two-part: table.column — preserve the qualified form as the join key.
        ast::Expr::CompoundIdentifier(parts) if parts.len() == 2 => Some(format!(
            "{}.{}",
            normalize_ident(&parts[0]),
            normalize_ident(&parts[1])
        )),
        // Three or more parts: schema.table.column — reject by returning None;
        // the caller will push the expression into non_equi which convert_expr
        // then rejects with SqlError::Unsupported.
        ast::Expr::CompoundIdentifier(_) => None,
        _ => None,
    }
}