php - 如何将这些多个 mysql_querys 转换为 1 个查询？

Question

我有两个表:用户和线程。创建线程时，它会将 user_id 作为 author_id 存储在表中。我想用相同的查询显示线程名称和作者的用户名。我目前正在使用两个查询，如下所示:

$query2 = mysql_query("SELECT author_id FROM threads WHERE id = $threadId") or die(mysql_error());
$result2 = mysql_fetch_array($query2);
$author_id = $result2['author_id'];
$query3 = mysql_query("SELECT username FROM users WHERE id = $author_id") or die(mysql_error());
$result3 = mysql_fetch_array($query3);
$author_name = $result3['username'];

Answer 1

<?php
$sql = '
    SELECT t.name, u.username
    FROM threads t
    JOIN users u ON t.author_id = u.id
    WHERE t.id = ' . (int)$threadId . '
';
list($thread_name, $author_name) = mysql_fetch_row(mysql_query($sql));

附言Mysql php extension已弃用。