Function select_sql 

pub fn select_sql(table: &str, columns: &[&str]) -> String

Build SELECT <c0>, <c1>, … FROM <table> projecting the declared columns in ColId order. Result-row order == columns order == ColId, which is what makes RowRef::col(i) an O(1) array index (05 §8.1). (The full constraint/start/filter WHERE lowering is 05 §4.4; out of scope here — the spike threads its own predicates.)