#include <mysql>

#define MYSQL_RESULT_LOGIN 1
#define MYSQL_RESULT_REGISTER 2

public OnGameModeInit()
{
	new MySQL:connection = mysql_init(LOG_ONLY_ERRORS, 1);
	mysql_connect("host", "username", "password", "database", connection);
	//I changed the host, username, password and database into default.
	return 1;
}

public OnPlayerDisconnect(playerid, reason)
{
    	mysql_close(connection);
    	return 1;
}

mysql_query_array("SELECT * FROM `users` WHERE `username` = 'pName' LIMIT 0,1", MYSQL_RESULT_LOGIN, {playerid}, connection);

C:\SAMP Server\Ultimate Stuntages\filterscripts\Zadmin1-MySQL.pwn(242) : error 017: undefined symbol "connection"
C:\SAMP Server\Ultimate Stuntages\filterscripts\Zadmin1-MySQL.pwn(282) : error 008: must be a constant expression; assumed zero
Pawn compiler 3.2.3664	 	 	Copyright © 1997-2006, ITB CompuPhase


2 Errors.

new MySQL:connection; // Declared with a global scope

connection = mysql_init(LOG_ONLY_ERRORS, 1); // Used inside a function/procedure

public OnMysqlQuery(resultid, spareid, MySQL:handle)
{
	switch (resultid)
	{
		case MYSQL_RESULT_LOGIN:
		{
			// process login with spareid as playerid
			SendClientMessage(spareid, COLOR_GREEN, "Succesfully logged in with MySQL!");
		}
		case MYSQL_RESULT_REGISTER:
		{
			// process register with spareid as playerid
		}
	}
	return 1;
}