create a program in c# to convert a query using natural language to a sql server query for a transaction table with fields date, channel, amonunt, customer_id fields in csharp in csharp

using System;
using System.Data.SqlClient;
using System.Linq;
using System.Text.RegularExpressions;
using Antlr4.Runtime;

namespace NaturalLanguageSql
{
    public class Program
    {
        public static void Main(string[] args)
        {
            const string connectionString = "Server=(local);Database=MyDatabase;Integrated Security=true;";

            // Define the grammar rules to parse the user query
            var query = "show me the total sales for customers who bought in the last month";

            // Use ANTLR to parse the user query and generate a structured data representation
            var inputStream = new AntlrInputStream(query);

            var lexer = new GrammarLexer(inputStream);
            var tokens = new CommonTokenStream(lexer);
            var parser = new GrammarParser(tokens);

            var parseTree = parser.query(); // generated parse tree

            // Map the structured data representation of the user query to a SQL Server query
            var fields = parseTree.fields().GetText().Replace(" ", "").Split(',');
            var dateRange = ParseDateRange(parseTree.dateRange().GetText());
            var sqlQuery = $"SELECT {string.Join(", ", fields)} FROM Transactions WHERE Date BETWEEN '{dateRange.Item1}' AND '{dateRange.Item2}';";

            // Execute the SQL query and process the results
            using (var connection = new SqlConnection(connectionString))
            {
                connection.Open();
                var command = new SqlCommand(sqlQuery, connection);
                var reader = command.ExecuteReader();

                while (reader.Read())
                {
                    // process each row of data
                }
            }
        }

        private static Tuple<DateTime, DateTime> ParseDateRange(string dateRange)
        {
            var match = Regex.Match(dateRange, @"last\s(\d*)\s(\w*)");
            var quantity = int.Parse(match.Groups[1].Value);
            var unit = Enum.Parse<DateUnit>(match.Groups[2].Value, true);

            var startDate = DateTime.Today.AddMonths((-1) * quantity).Date;
            var endDate = DateTime.Today.Date;

            switch (unit)
            {
                case DateUnit.Day:
                    startDate = endDate.AddDays((-1) * quantity);
                    break;
                case DateUnit.Month:
                    startDate = endDate.AddMonths((-1) * quantity);
                    break;
                case DateUnit.Year:
                    startDate = endDate.AddYears((-1) * quantity);
                    break;
            }

            return new Tuple<DateTime, DateTime>(startDate, endDate);
        }

        private enum DateUnit
        {
            Day,
            Month,
            Year
        }
    }
}
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