[shadowdog]

PHP код:

stock SaveData(playerid)
{
    new query[128];
    mysql_format(mysql, query, sizeof(query), "UPDATE `playerdata` SET `Admin`=%d, `VIP`=%d, `Money`=%d, `Helper`=%d, `Kills`=%d, `Deaths`=%d WHERE #account_id# = %d",\
    PlayerData[playerid][pAdmin], PlayerData[playerid][pVIP], PlayerData[playerid][pCash], PlayerData[playerid][pHelper], PlayerData[playerid][pKills], PlayerData[playerid][pDeaths], #AccountID#);
    mysql_tquery(mysql, query, "", "");
    return 1;
} 


Add a WHERE statement to tell the constructor which row should be updated. It should be the account ID or the username, whichever you use.

The mysql_tquery is fine.