using System;

using System.Linq;

using System.Text;              

public class Program

{

    public static void Main()

    {

        DateTime start = new DateTime(2015, 2, 19);

        DateTime end = new DateTime(2016, 2, 19);

        Console.WriteLine(GenerateDateRangeClause(start, end));

    }

    public static string GenerateDateRangeClause(DateTime date1, DateTime date2)

        {

            StringBuilder whereClause = new StringBuilder();

​

            if (date1.Year != date2.Year)

            {

                whereClause.AppendFormat("(Day IS NOT NULL AND (");

                whereClause.AppendFormat("(Month = {0} AND Day >= {1} AND Year = {2})", date1.Month, date1.Day, date1.Year); // Start year & start month

                whereClause.Append(" OR ");

                whereClause.AppendFormat("(Month > {0} AND Year = {1})", date1.Month, date1.Year); //Start year, after start month

                whereClause.Append(" OR ");

                whereClause.AppendFormat("(Year > {0} AND Year < {1})", date1.Year, date2.Year); // Years in between

                whereClause.Append(" OR ");

                whereClause.AppendFormat("(Month = {0} AND Day <= {1} AND Year = {2})", date2.Month, date2.Day, date2.Year); // end year & end month

                whereClause.Append(" OR ");

                whereClause.AppendFormat("(Month < {0}  AND Year = {2})", date2.Month, date2.Day, date2.Year); // end year before end month

                whereClause.Append("))");

            }

            else if (date1.Month != date2.Month)

            {

                whereClause.AppendFormat("(Day IS NOT NULL AND Year = {0} AND (", date1.Year);

                whereClause.AppendFormat("(Month = {0} AND Day >= {1})", date1.Month, date1.Day); // Start Month

                whereClause.Append(" OR ");

                whereClause.AppendFormat("(Month > {0} AND Month < {1})", date1.Month, date2.Month); // Month(s) in between

                whereClause.Append(" OR ");

                whereClause.AppendFormat("(Month = {0} AND Day <= {1})", date2.Month, date2.Day); // End month

                whereClause.Append("))");

            }

            else

            {

                whereClause.AppendFormat("(Day IS NOT NULL AND Year = {0} AND Month = {1} AND Day BETWEEN {2} AND {3})", date1.Year, date1.Month, date1.Day, date2.Day);

            }

​

            return whereClause.ToString();

        }

}