计算朋友数量并显示为数字PHP

问题描述：

I have been creating a social networking site and have a friends system in place where the users can add/remove each other and it displays the users friends and profile pictures. All i need now is just to retrieve a total number of friends rather than the friends being listed individually for example (Sam has 21 friends). My 'friends' table looks like this.

    id   user_one   user_two
     4          3         9
     5          3         7
     6         11         3

I have tried to run a query:

        $friend_count = mysql_query("SELECT count(*) FROM friends WHERE
        ($user_one = '$id' AND $user_two = '$id')";

But i am not sure how to then display the number or if this is even along the right lines.

I am fairly new to PHP so any help would be greatly appreciated!

我一直在创建一个社交网站，并且有一个朋友系统，用户可以在其中添加/删除对方它显示用户朋友和个人资料图片。我现在需要的只是检索朋友总数而不是单独列出的朋友（Sam有21个朋友）。我的'朋友'表看起来像这样。 p>

  id user_one user_two 
 4 3 9 
 5 3 7 
 6 11 3 
  code>  pre  > 
 
 我试图运行查询： p> 
 
 
  $ friend_count = mysql_query（“SELECT count（*）FROM friends WHERE 
（$ user_one =  '$ id'AND $ user_two ='$ id'）“; 
  code>  pre> 
 
 但我不知道如何显示数字或者是否沿着 正确的行。 p> 
 
 
我是PHP的新手，所以任何帮助都将不胜感激！ p> 
  div>

答

your query should be:

$friend_count = mysql_query("SELECT count(*) FROM friends WHERE
        ($user_one = '$id' OR $user_two = '$id')");

you should use mysqli because mysql is deprecated, so you can do like this:

$link = mysqli_connect("localhost", "my_user", "my_password", "world");
$query = mysqli_query($link, "SELECT count(*) as count_friends FROM friends WHERE
            ($user_one = '$id' OR $user_two = '$id')");
$row = mysqli_fetch_array($query);
$count_friends = $row['count_friends'];

答

See what you're doing is this:

SELECT count(*) FROM friends WHERE ($user_one = '$id' AND $user_two = '$id')

It is looking in friends for rows where user_one AND user_two (which should not be variables... or between brackets) are the same.

So for something to be counted: user_one must be user_two

I imagine your intention is two check whether $id is either found in user_one or user_two throughout the table.

Meaning you need OR and not AND

Corrected Select statement:

SELECT count(*) FROM friends WHERE user_one = '$id' OR user_two = '$id'

UPDATE - Should do what you need:

$select= "SELECT count(*) FROM friends WHERE user_one = '$id' OR user_two = '$id'";
$conn= mysqli_connect("localhost", "USER", "PASSWORD", "test");
$query = mysqli_query($conn, $select);
$row = mysqli_fetch_array($query);
echo reset($row);

计算朋友数量并显示为数字PHP

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