Php 再次查询并始终仅读取第一条记录。相反，您应该运行一次查询，并在循环中调用mysql\u fetch\u array（）

例如：

$myFriends = mysql_query("Select * from friends where userid1 = $myUsername AND friendstatus = '1'");
while ($friend = mysql_fetch_array($myFriends) {
    $friend_1 = $friend['userid2'];
    friendsLookup($friend_1,$myUsername);
}

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希望以上帮助

请不要忘记用mysql\u real\u escape\u字符串清理$myUsername变量！此代码易受SQL注入攻击。请不要忘记使用mysql\u real\u escape\u字符串清理$myUsername变量！此代码易受SQL注入攻击。

$myUsername = $_GET['myFriends'];
if(isset($myUsername)){
        $friends = mysql_query("Select * from friends where userid1 = $myUsername AND friendstatus = '1'");
        $friends2 = mysql_query("Select * from friends where userid2 = $myUsername AND friendstatus = '1'");
        if(mysql_num_rows($friends) > 0 OR mysql_num_rows($friends2) >0 ) {

echo '<table><tr><td>Username </td><td> Location</td></tr>';
        $col1rows = mysql_num_rows($friends);
        $col2rows = mysql_num_rows($friends2);
            }
        for ($i=0; $i<$col1rows;$i++){
            $myFriends = mysql_query("Select * from friends where userid1 = $myUsername AND friendstatus = '1'");
                $friend = mysql_fetch_array($myFriends);
                $friend_1 = $friend['userid2'];
                friendsLookup($friend_1,$myUsername);
            }
        for ($i=0; $i<$col2rows;$i++){
            $myFriends_2 = mysql_query("Select * from friends where userid2 = $myUsername AND friendstatus = '1'");
                $friend = mysql_fetch_array($myFriends_2);
                $friend_2 = $friend['userid1'];
                friendsLookup($friend_2,$myUsername);
                }
            }

$myUsername = $_GET['myFriends'];
if(isset($myUsername)){
        $friends = mysql_query("
        SELECT userid1 as friendId
        FROM friends
        WHERE userid2 = $myUsername AND friendstatus = 1
        UNION
        SELECT userid2 as friendId
        FROM friends
        WHERE userid1 = $myUsername AND friendstatus = 1
        ");

        if(mysql_num_rows($friends) > 0) {
            echo '<table><tr><td>Username </td><td> Location</td></tr>';
            while($friend = mysql_fetch_array($friends)) {
                $friend_data = friendsLookup($friend['friendId'],$myUsername);
                //display friend data here
            }
            echo '</table>';
        }
}

$sql = "SELECT * FROM user u, friend f WHERE f.userid1 = $myUsername AND f.friendstatus = '1' AND u.userid = f.userid2
UNION
SELECT * FROM user u, friend f WHERE f.userid2 = $myUsername AND f.friendstatus = '1' AND u.userid = f.userid1";

$sql = "SELECT * FROM (
SELECT * FROM user u, friend f WHERE f.userid1 = $myUsername AND f.friendstatus = '1' AND u.id = f.userid2
UNION
SELECT * FROM user u, friend f WHERE f.userid2 = $myUsername AND f.friendstatus = '1' AND u.id = f.userid1 ) tblResult r
ORDER BY r.first_name ASC";

$query = mysql_query( $sql );
while ( $col = mysql_fetch_array( $query ) ){
  ?>
  <!-- DO YOUR THING HERE WITH PHP -->
  <?php
}

$myFriends = mysql_query("Select * from friends where userid1 = $myUsername AND friendstatus = '1'");
$friend = mysql_fetch_array($myFriends);

$friend = mysql_fetch_array($friends);

SELECT (CASE $myUsername
    WHEN `userid1` THEN `userid2`
    WHEN `userid2` THEN `userid1`
END) AS `friend_ids`
FROM `friends`
WHERE $myUsername IN (`userid1`, `userid2`)
AND `friendstatus` = 1;

$myFriends = mysql_query("Select * from friends where userid1 = $myUsername AND friendstatus = '1'");
while ($friend = mysql_fetch_array($myFriends) {
    $friend_1 = $friend['userid2'];
    friendsLookup($friend_1,$myUsername);
}