1// Java with JDBC
2import java.sql.*;
3
4public class Main {
5    public static void main(String[] args) {
6        String url = "jdbc:sqlite:your_database.db";
7        String query = "SELECT customer_id, COUNT(visit_id) AS count_no_trans FROM Visits LEFT JOIN Transactions ON Visits.visit_id = Transactions.visit_id WHERE Transactions.transaction_id IS NULL GROUP BY customer_id;";
8        
9        try (Connection conn = DriverManager.getConnection(url);
10             Statement stmt = conn.createStatement();
11             ResultSet rs = stmt.executeQuery(query)) {
12
13            while (rs.next()) {
14                System.out.println("customer_id: " + rs.getInt("customer_id") + ", count_no_trans: " + rs.getInt("count_no_trans"));
15            }
16        } catch (SQLException e) {
17            System.out.println(e.getMessage());
18        }
19    }
20}

#include <iostream>
#include <string>
#include <sqlite3.h>

void executeSQL(const std::string &query) {
    sqlite3 *db;
    char *zErrMsg = nullptr;
    int rc;

    rc = sqlite3_open("your_database.db", &db);
    if(rc) {
        std::cerr << "Can't open database: " << sqlite3_errmsg(db) << std::endl;
        return;
    }

    rc = sqlite3_exec(db, query.c_str(), callback, 0, &zErrMsg);
    if(rc != SQLITE_OK) {
        std::cerr << "SQL error: " << zErrMsg << std::endl;
        sqlite3_free(zErrMsg);
    }
    sqlite3_close(db);
}

int main() {
    std::string query = "SELECT customer_id, COUNT(visit_id) AS count_no_trans FROM Visits WHERE NOT EXISTS (SELECT * FROM Transactions WHERE Visits.visit_id = Transactions.visit_id) GROUP BY customer_id;";
    executeSQL(query);
    return 0;
}

// Note: Make sure to implement the callback function and handle the database initialization and cleanup properly. The query provided is SQL and should be run on a SQL-compliant database like SQLite3.