如何对这样的东西进行OR查询？
//Query
$sql = "select `Friend_status` from `friendship_box` where
`system_id` = '$sid' and `friend_id` = '$friendis' OR
`system_id='$friendis' and `friend_id` = '$sid'";
$query = mysql_query($sql) or die ("Error: ".mysql_error());
while ($row = mysql_fetch_array($query)){
$activity = htmlspecialchars($row['Friend_status']);
}
mysql_free_result($query);
select `Friend_status` from `friendship_box`
where (`system_id` = '$sid' and `friend_id` = '$friendis')
OR (`system_id`='$friendis' and `friend_id` = '$sid')
您错过了此处的`：
...OR (`system_id` <--