[Sinner]

To check if the player is banned (basically by checking if the ip occurs in the bans table):

pawn Код:

stock IsPlayerBanned(playerid) {
    new query[128], player_ip[16], bool:banned = false;
    GetPlayerIp(playerid, player_ip, sizeof(player_ip));
    format(query, sizeof(query), "SELECT * FROM `bans` WHERE `ip` = '%s'", player_ip);
    mysql_query(query);
    mysql_store_result();
    banned = mysql_num_rows>0;
    mysql_free_result();
    return banned;
}

To unban the player (remove his 'record'):

pawn Код:

stock UnbanPlayer(ip[]) {
    new query[128];
    format(query, sizeof(query), "DELETE FROM `bans` WHERE `ip` = '%s'", ip);
    mysql_query(query);
}

Hope that helped.