PHP和多個DB選擇

Question

我有兩張表，我需要從中提取信息，但第二張表中的數據取決於我從第一張中獲得的信息。有沒有簡單的方法來處理這個問題？

<?php 
    mysql_connect('localhost', 'root', 'root') or die(mysql_error()); 
    mysql_select_db('stadium') or die(mysql_error()); 

    $result = mysql_query("SELECT * FROM events"); 

    $result2 = mysql_query("SELECT name FROM competitions WHERE id='$row[competition_id]' "); 

    while($row = mysql_fetch_array($result)) { 
    echo "<tr id=\"" . $row['id'] . "\"> \n<td>" . $row['name'] . "</td>"; 
    echo "<td>" . $row['competition_id'] . "</td>"; 
    echo "<td>" . $row['date'] . "</td></tr>"; 
    } 
?> 

Answer 1

使用JOIN。

SELECT e.*, c.name as competition_name FROM events e LEFT JOIN competitions c on c.id = e.competition_id