using System;

using System.Text.RegularExpressions;

​

class Program

{

    static void Main(string[] args)

    {

        string sql = "SELECT * FROM ARTICOL_UNIC a INNER JOIN @IDArticol p.id = a.ID && p.test = a.TEST && @IDConcern i ON i.id = a.ID";

        string paramName = "@IDArticol";

        // Find the specified parameter alias in the SQL string

        Match match = Regex.Match(sql, $@"(?i){paramName}\s+(\w+)\s+\b(\w+)\b\s+\1\.id\s*=");

        if (match.Success)

        {

            // Replace "=" with "<>"

            string replaced = Regex.Replace(match.Value, "=", "<>");

            // Replace the original SQL string with the updated string

            sql = sql.Replace(match.Value, replaced);

        }

​

        Console.WriteLine(sql);

    }

}