Introduction
First of all, it's been a long time since I didn't release anything on this forum. So today I'm gonna release something that is, I think pretty useful for those who wanna learn how to create a registration system with mysql threaded queries. Many people use non-threaded queries because they think it's harder to use threaded queries. But in fact, it's just way easier than you thought. So today, I will teach so you how to make a registration system using mysql threaded queries(version r33 and above). In this tutorial, we will save player's name, password, ip, admin level, vip level, money, and player's position.

Things that you need
- Mysql plugin - Download it and place the files in your server's directory.
- Whirlpool - Download it and place the file in your server's directory.
- xampp - Download it and install it in your pc.

Creating a new database and table
- Run xampp-control and you should see this.

- Click Start on Apache and MySQL. If you have skype opened, close it.

- Click Admin at MySQL to manage/create your database.

- Click on Databases to create a new database.

- Name your server database and click Create (In this tutorial will use "server" as our database)

- After you click the Create button, you will notice your database has been created by looking at left side of your screen. Click your database to manage your table's name and column.

- You will see this screen after you click your database. (More explanation in the image)

- After you click Go button, it will redirect to you the next page where you can manage your table's column.

Congratulations, you have created your database and table! Now;

Let's start scripting!

pawn Code:
//First, of course we need to include these files first
#include <a_samp> //Without this, we won't be able to use all samp functions/callbacks
#include <a_mysql> //Without this, we won't be able to use all mysql functions

pawn Code:
//Let's define our mysql settings
#define host "localhost" //This will be your mysql host. Default for xampp is localhost
#define user "root" //This will be your mysql username. Default for xampp is root
#define db "server" //This is your database name. Remember we have created a database called server before.
#define pass "" //This is your mysql password. In xampp, the password didn't set. So leave it empty.

//dialogs
#define dregister 6287 //dialog register id
#define dlogin 6288 // ^

pawn Code:
//Global variables. We will use them later
static
mysql, //This variable will be used to manage our database
Name[MAX_PLAYERS][24], //We will use this variable to store player's name.
IP[MAX_PLAYERS][16] //We will use this variable to store player's ip.
;

pawn Code:
native WP_Hash(buffer[], len, const str[]); //whirlpool, for hashing our password

pawn Code:
//Now let's create an enumerator that holds player's information
enum PDATA //We name our enumerator as PDATA (which stands for PlayerDATA). You can name it however you want.
{
ID, //Will be used later to store player's ID from database so we can use it anywhere later
Password[129], //We will load player's password into this varible from database
Admin, //We will load player's admin level from database into this variable so we can use it anywhere later.
VIP, //We will load player's VIP level from database into this variable so we can use it anywhere later.
Money, //We will load player's money from database into this variable so we can use it anywhere later.
Float:posX, //We will load player's X position from database into this variable so we can use it anywhere later.
Float:posY, //We will load player's Y position from database into this variable so we can use it anywhere later.
Float:posZ //We will load player's Z from database into this variable so we can use it anywhere later.

}
new pInfo[MAX_PLAYERS][PDATA]; //Variable that stores enumerator above

pawn Code:
public OnGameModeInit()
{
mysql_log(LOG_ERROR | LOG_WARNING | LOG_DEBUG); //Let's enable debugging so we can detect a problem(if there is)
mysql = mysql_connect(host, user, db, pass); //This function will connect your server to database. Remember we have defined our host, username, database and password. It's time to use it here.
if(mysql_errno(mysql) != 0) print("Could not connect to database!"); //This will tell if your connection to database is successful or not. If it's not, check your host, username, database and password. Make sure they all right.
return 1;
}

pawn Code:
//Checking player's account if they are registered or not.
public OnPlayerConnect(playerid)
{
new query[128]; //We use this variable to format our query
GetPlayerName(playerid, Name[playerid], 24); //Getting player's name
GetPlayerIp(playerid, IP[playerid], 16); //Getting layer's IP
mysql_format(mysql, query, sizeof(query),"SELECT `Password`, `ID` FROM `players` WHERE `Username` = '%e' LIMIT 1", Name[playerid]);
// - We use mysql_format instead of format because we can use an %e specifier. %e specifier escapes a string so we can avoid sql injection which means we don't have to use mysql_real_escape_string
// - Formatting our query; SELECT `Password`, `ID` FROM `players` WHERE `Username`='%e' means we are selecting a Password and ID's column in the table that has player's name in Username column.
// - LIMIT 1; we only need 1 result to be shown
mysql_tquery(mysql, query, "OnAccountCheck", "i", playerid);
//lets execute the formatted query and when the execution is done, a callback OnAccountCheck will be called
//You can name the callback however you like

return 1;
}

pawn Code:
//OnAccountCheck is a custom callback which means it has to be forwarded.
forward OnAccountCheck(playerid);

//Now once the query has been processed;
public OnAccountCheck(playerid)
{
new rows, fields; //a variable that will be used to retrieve rows and fields in the database.
cache_get_data(rows, fields, mysql);//let's get the rows and fields from the database.
if(rows) //if there is row
{//then
cache_get_field_content(0, "PASS", pInfo[playerid][Password], mysql, 129);
//we will load player's password into pInfo[playerid][Password] to be used in logging in
pInfo[playerid][ID] = cache_get_field_content_int(0, "ID"); //now let's load player's ID into pInfo[playerid][ID] so we can use it later
printf("%s", pInfo[playerid][Password]); //OPTIONAL: Just for debugging. If it didn't show your password, then there must be something wrong while getting player's password
ShowPlayerDialog(playerid, dlogin, DIALOG_STYLE_INPUT, "Login", "In order to play, you need to login", "Login", "Quit"); //And since we found a result from the database, which means, there is an account; we will show a login dialog
}
else //if we didn't find any rows from the database, that means, no accounts were found
{
ShowPlayerDialog(playerid, dregister, DIALOG_STYLE_INPUT, "Register", "In order to play, you need to register.", "Register", "Quit");
//So we show them a dialog register
}
return 1;
}

pawn Code:
//Now let's response to the login and register dialog
public OnDialogResponse(playerid, dialogid, response, listitem, inputtext[])
{
switch(dialogid)
{
case dlogin: //login dialog
{
if(!response) Kick(playerid); //if they clicked Quit, we will kick them
new hpass[129]; //for password hashing
new query[100]; // for formatting our query.
WP_Hash(hpass, 129, inputtext); //hashing inputtext
if(!strcmp(hpass, pInfo[playerid][Password])) //remember we have loaded player's password into this variable, pInfo[playerid][Password] earlier. Now let's use it to compare the hashed password with password that we load
{ //if the hashed password matches with the loaded password from database
mysql_format(mysql, query, sizeof(query), "SELECT * FROM `players` WHERE `Username` = '%e' LIMIT 1", Name[playerid]);
//let's format our query
//We select all rows in the table that has your name and limit the result to 1
mysql_tquery(mysql, query, "OnAccountLoad", "i", playerid);
//lets execute the formatted query and when the execution is done, a callback OnAccountLoad will be called
//You can name the callback however you like
}
else //if the hashed password didn't match with the loaded password(pInfo[playerid][Password])
{
//we tell them that they have inserted a wrong password
ShowPlayerDialog(playerid, dlogin, DIALOG_STYLE_INPUT, "Login", "In order to play, you need to login\nWrong password!", "Login", "Quit");
}
}
case dregister: //register dialog
{
if(!response) return Kick(playerid); //if they clicked Quit, we will kick them
if(strlen(inputtext) < 6) return ShowPlayerDialog(playerid, dregister, DIALOG_STYLE_INPUT, "Register", "In order to play, you need to register.\nYour password must be at least 6 characters long!", "Register", "Quit");
//strlen checks a lenght of a string. so if player types their password that is lower than 6, we tell them; Your password must be at least 6 characters long!
new query[300];
WP_Hash(pInfo[playerid][Password], 129, inputtext); //hashing inputtext
mysql_format(mysql, query, sizeof(query), "INSERT INTO `players` (`Username`, `Password`, `IP`, `Admin`, `VIP`, `Money`, `PosX` ,`PosY`, `PosZ`) VALUES ('%e', '%s', '%s', 0, 0, 0, 0.0, 0.0, 0.0)", Name[playerid], pInfo[playerid][Password], IP[playerid]);
//Now let's create a new row and insert player's information in it
mysql_tquery(mysql, query, "OnAccountRegister", "i", playerid);
//let's execute the query
}
}
return 1;
}

pawn Code:
forward OnAccountLoad(playerid);
forward OnAccountRegister(playerid);
//let's load player's information
public OnAccountLoad(playerid)
{
pInfo[playerid][Admin] = cache_get_field_content_int(0, "Admin"); //we're getting a field 4 from row 0. And since it's an integer, we use cache_get_row_int
pInfo[playerid][VIP] = cache_get_field_content_int(0, "VIP"); //Above
pInfo[playerid][Money] = cache_get_field_content_int(0, "Money");//Above
pInfo[playerid][posX] = cache_get_field_content_float(0, "PosX");//Above. Since player's position is a float, we use cache_get_field_content_float
pInfo[playerid][posY] = cache_get_field_content_float(0, "PosY");//Above
pInfo[playerid][posZ] = cache_get_field_content_float(0, "PosZ");//Above

GivePlayerMoney(playerid, pInfo[playerid][Money]);//Let's set their money
//For player's position, set it once they spawn(OnPlayerSpawn)
SendClientMessage(playerid, -1, "Successfully logged in"); //tell them that they have successfully logged in
return 1;
}

public OnAccountRegister(playerid)
{
pInfo[playerid][ID] = cache_insert_id(); //loads the ID of the player in the variable once they registered.
printf("New account registered. ID: %d", pInfo[playerid][ID]); //just for debugging.
return 1;
}

pawn Code:
public OnPlayerDisconnect(playerid, reason)
{
new query[128], Float:pos[3]; //query[128] is for formatting our query and Float:pos[3] is for getting and saving player's position
GetPlayerPos(playerid, pos[0], pos[1], pos[2]); //let's get player's position when they leave your server
mysql_format(mysql, query, sizeof(query), "UPDATE `players` SET `Admin`=%d, `VIP`=%d, `Money`=%d, `posX`=%f, `posY`=%f, `posZ`=%f WHERE `ID`=%d",\
pInfo[playerid][Admin], pInfo[playerid][VIP], pInfo[playerid][Money], pos[0], pos[1], pos[2], pInfo[playerid][ID]);
//We update the table(`players`) by getting player's admin level, vip level, money, and positions and save them in the database
mysql_tquery(mysql, query, "", "");
//let's execute the query.
return 1;
}

pawn Code:
public OnPlayerSpawn(playerid)
{
SetPlayerPos(playerid, pInfo[playerid][posX], pInfo[playerid][posZ], pInfo[playerid][posZ]);
//Set player's position to the last saved position.
return 1;
}

Thank you for reading my tutorial. If there's a mistake somewhere, please let me know.