[Miguel]

This is how I do it:

pawn Код:

stock CheckAccount(playerid)
{
  MySQLCheck();

  new
    query[70];

  format(query, sizeof(query), "SELECT * FROM `players` WHERE Nickname = '%s'", Player[playerid][Name]);
  mysql_query(query);
  mysql_store_result();
  if(mysql_num_rows() > 0) Player[playerid][Registered] = 1;
  else Player[playerid][Registered] = 0;
  mysql_free_result();
}

pawn Код:

public OnPlayerConnect(playerid)
{
  ...
  CheckAccount(playerid);
  if(Player[playerid][Registered] == 1) BlaBlaBla;
  else BlaBlaBla2;
  return 1;
}