Question

我正在尝试创建一个社交网络。在个人资料详细信息中，我想显示该个人资料用户的至少10个朋友。我用过：

$connect = mysqli_connect("...","...","...","dbname"); //NOT REALLY IMPORTANT
$find = "SELECT * FROM friendslist WHERE user1 = '$myusername'";
$exec = mysqli_query($connect,$find);

while($row=mysqli_fetch_assoc($exec)) {
$friendusername = $row['user2'];

$con2 = "SELECT * FROM users WHERE username = '$friendusername' ";
$exec2 = mysqli_query($con,$con2);
$row2 = myslqi_fetch_assoc($exec2);

echo $row2['firstname']."<br/>";

我的桌子：

FOR friends:
id, user1, user2

FOR users
id, username, firstname

它会显示我的所有朋友，如果我有20个朋友，它将显示所有20个朋友。如何将其限制为仅显示10？

Answer 1

尝试：

$find = "SELECT * FROM friendslist WHERE user1 = '$myusername' LIMIT 0, 10";

Answer 2

就像@ Danijel的答案一样，很好的选择是加入表格。

首先加入表格，使用 f.user1 ='$ myusername'获取好友列表，然后将其限制为十个。

PD：不要在循环中进行查询，这对性能不利

$find = "SELECT * 
         FROM friendslist  f, users u
         WHERE     f.user2 = u.username 
               AND f.user1 = '$myusername' 
         LIMIT 10";

        $exec = mysqli_query($connect,$find);

        while($row=mysqli_fetch_assoc($exec)) {

              echo $row2['firstname']."<br/>";
        }

Answer 3

加入查询并限制为10。

"SELECT * FROM friendslist LEFT JOIN users ON friendslist.user2=users.username WHERE user1 = '$myusername' LIMIT 10"

将MySQL搜索输出限制为10

3 个答案: