// src/SQLQueryAdvisor.java import java.util.; import java.util.regex.;

/**

• SQLQueryAdvisor

• • Heuristic parsing of simple SELECT queries and rule-based advice */ public class SQLQueryAdvisor { public static List advise(String query) { String q = query.trim().toLowerCase(); List adv = new ArrayList<>(); if (q.contains("select *")) adv.add("Avoid SELECT * — specify required columns to reduce IO."); Pattern p = Pattern.compile("from\s+(\w+)", Pattern.CASE_INSENSITIVE); Matcher m = p.matcher(query); if (m.find()) { adv.add("Detected table: " + m.group(1)); } if (q.contains("where")) { adv.add("Query has WHERE — good. Check whether predicates are supported by indexes (equality predicates benefit most)."); if (q.contains("like")) adv.add("LIKE may not use an index; consider trigram or full-text indexes if needed."); } else { adv.add("No WHERE clause — this will likely cause a full table scan."); } if (q.contains("order by")) adv.add("ORDER BY can be expensive — consider covering indexes or LIMIT pushdown."); return adv; }

  public static void main(String[] args) { String[] examples = { "SELECT * FROM users WHERE email = 'a@b.com';", "SELECT id, name FROM orders ORDER BY created_at DESC;", "SELECT count(*) FROM products;" }; for (String e : examples) { System.out.println("Query: " + e); for (String a : advise(e)) System.out.println(" - " + a); System.out.println(); } } }