public OnPlayerConnect(playerid)
{
    new query[256];
    format(query, sizeof(query), "SELECT `user` FROM `playerdata` WHERE user = '%s'", GetPName(playerid));
    mysql_query(query);
    mysql_store_result();
    new rows = mysql_num_rows();
    mysql_free_result();
    
    if(rows != 0)
    {
       
        ShowPlayerDialog(playerid, DIALOG_LOGIN, DIALOG_STYLE_INPUT, ""Blue"Please log-in", ""White"Welcome back to "Red""SERVER_NAME""White"!\n"White"In order to start playing, you have to log-in!\n\n"White"Please insert "Red"your"White" password below:", "Login", "Cancel");
    }
    else
    {
        ShowPlayerDialog(playerid, DIALOG_REGISTER, DIALOG_STYLE_INPUT, ""Blue"Please register",""White"Welcome to "Red""SERVER_NAME""White"!\n"White"In order to start playing, you have to register!\n\n"White"Please insert a password below:", "Register", "Cancel");
    }
    return 1;
}