using System;

public class Program

{

    public static void Main()

    {

        var query1 = @$"SELECT COUNT(*) FROM [dbo].[campaign] WHERE created_at <= GETUTCDATE()"

            .WhereCampaignIsActive();

        var query2 = @$"SELECT COUNT(*) FROM [dbo].[campaign]"

            .WhereCampaignIsActive();

        Console.WriteLine(query1);

        Console.WriteLine(query2);

    }

}

​

​

    public static class QueryStringExtensions

    {

        public static string WhereCampaignIsActive(this string query, string prefix = null)

        {

            if (query.Contains("WHERE"))

            {

                return query + $" AND {prefix}published_status = 2 AND {prefix}end_date >= GETUTCDATE() " +

                    $"AND {prefix}start_date <= GETUTCDATE() AND {prefix}suspended = 0";

            }

            else

            {

                return query + $" WHERE {prefix}published_status = 2 AND {prefix}end_date >= GETUTCDATE() " +

                    $"AND {prefix}start_date <= GETUTCDATE() AND {prefix}suspended = 0";

            }

        }

    }