問關於MySQL表

Question

我有2個表

usrfrnd_table

user_id friend_id 
__________________ 
1   1 

2   5 

3   1 

2   1 

和usr_table

id fullname 
________________ 

1 John Doe 

2 George Cann 
... 

如何從表usr_table與循環呼應例如ID 2所有的朋友？ 試過這段代碼。但不工作

$stmt = "SELECT fullname FROM usr_table INNER JOIN usrfrnd_table ON usr_table.id=usrfrnd_table.friend_id WHERE usrfrnd_table.user_id='$id'"; 
    $result=$db->query($stmt); 
    foreach($result as $rec){ 
     echo "<li><a href=user.php?id=".$rec['id']."'>". $rec['fullname'] . "</a></li>"; 
    } 

Answer 1

試試這個：

$stmt = "SELECT id, fullname FROM usr_table INNER JOIN usrfrnd_table ON usr_table.id=usrfrnd_table.friend_id WHERE usrfrnd_table.user_id=2"; 
$result=mysql_query($stmt); 
foreach($result as $rec){ 
    echo $rec['fullname'] . "<br>"; 
} 

Answer 2

查詢會是這個樣子：

select fullname from usr_table inner join usrfrnd_table ON (usr_table.id = usrfrnd_table.friend_id) WHERE usrfrnd_table.user_id = 2; 

Answer 3

如果我理解正確的話，你是想顯示所有好友的用戶2.你需要做一個內部連接。

SELECT usr_table.fullname FROM usrfrnd_table, usr_table WHERE (usrfrnd_table.friend_id = usr_table.id) AND (usrfrnd_table.user_id = 2)