1using System;
2using System.Data;
3using System.Data.SQLite;
4
5class Program
6{
7    static void Main()
8    {
9        string connectionString = "Data Source=your_database.db;Version=3;";
10        using (SQLiteConnection connection = new SQLiteConnection(connectionString))
11        {
12            connection.Open();
13
14            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;";
15            using (SQLiteCommand command = new SQLiteCommand(query, connection))
16            {
17                using (SQLiteDataReader reader = command.ExecuteReader())
18                {
19                    while (reader.Read())
20                    {
21                        Console.WriteLine($"customer_id: {reader["customer_id"]}, count_no_trans: {reader["count_no_trans"]}");
22                    }
23                }
24            }
25        }
26    }
27}