sql helper class in c#

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;

namespace Common
{
    public static class SQLFunctions
    {
        public static string PrepareSQLString(string sqlQuery)
        {
            sqlQuery = sqlQuery.Replace("'", "''");

            return sqlQuery;
        }

        public static string PrepareDateString(DateTime date)
        {
            string output = "";

            output = date.Day + "-" + CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(date.Month) + "-" + date.Year + " " + date.Hour + ":" + date.Minute + ":" + date.Second + ":" + date.Millisecond;

            return output;
        }
        public static int PrepareSQLString1(int dd)
        {
            int kkdd = 0;
            kkdd = Convert.ToInt32(dd.ToString());
            return kkdd;

        }
        public static decimal PrepareSQLString15(decimal dd)
        {
            decimal kkdd = 0.00m;
            kkdd = Convert.ToInt32(dd.ToString());
            return kkdd;

        }
    }

   
}