using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var test1 = SqlLike("PRT23626%", "PRT2362666");

        var test2 = SqlLike("PRT23626%", "PRT12362666");

        var test3 = SqlLike("PRT23%626%", "PRT230006266600");

        var test4 = SqlLike("PRT23%626%8", "PRT2300062660068");

        var pattern = @"^P200[a-z0-9\-]+555[a-z0-9\-]+";

        var test5 = RegexMatch(pattern, "P200565055501");

        var test6 = RegexMatch(pattern, "1P200565055501");

        Console.WriteLine(test1.ToString());

        Console.WriteLine(test2.ToString());

        Console.WriteLine(test3.ToString());

        Console.WriteLine(test4.ToString());

        Console.WriteLine(test5.ToString());

        Console.WriteLine(test6.ToString());

    }

    public static bool RegexMatch(string pattern, string value)

    {

        Match match = Regex.Match(value, pattern);

        return match.Success;

    }

    public static bool SqlLike(string pattern, string value)

        {

            bool isMatch = true,

                isWildCard = false,

                endOfPattern = false;

            int lastWildCard = -1;

            int patternIndex = 0;

            char currentPatternChar = '\0';

            for (int i = 0; i < value.Length; i++)

            {

                char currentValueChar = value[i];

                endOfPattern = (patternIndex >= pattern.Length);

                if (!endOfPattern)

                {

                    currentPatternChar = pattern[patternIndex];

                    if (!isWildCard && currentPatternChar == '%')

                    {

                        lastWildCard = patternIndex;

                        isWildCard = true;

                        while (patternIndex < pattern.Length && pattern[patternIndex] == '%')

                        {

                            patternIndex++;

                        }

                        currentPatternChar = patternIndex >= pattern.Length ? '\0' : pattern[patternIndex];

                    }

                }

                if (isWildCard)

                {

                    if (char.ToUpper(currentValueChar) == char.ToUpper(currentPatternChar))

                    {

                        isWildCard = false;

                        patternIndex++;

                    }

                }

                else

                {

                    //Comparing the pattern current char with the value current char

                    //If they don't match,

                    if (char.ToUpper(currentValueChar) == char.ToUpper(currentPatternChar))

                    {

                        patternIndex++;

                    }

                    else

                    {

                        if (lastWildCard >= 0)

                            patternIndex = lastWildCard;

                        else

                        {

                            isMatch = false;

                            break;

                        }

                    }

                }

            }

            //If endOfPattern is true, then the entire pattern has been compared to the value

            endOfPattern = (patternIndex >= pattern.Length);

            if (isMatch && !endOfPattern)

            {

                bool isOnlyWildCards = true;

                for (int i = patternIndex; i < pattern.Length; i++)

                {

                    if (pattern[i] != '%')

                    {

                        isOnlyWildCards = false;

                        break;

                    }

                }

                if (isOnlyWildCards)

                    endOfPattern = true;

            }

            return isMatch && endOfPattern;

        }

}