SQL - 如何在另一個表中使用選定的ID？

Question

SQL表：
用戶= ID，姓名，電子郵件..
英雄= ID，姓名，級別..
所有者=用戶ID，heroid

我有兩個疑問：

$result = mysql_query("SELECT heroid FROM owner WHERE userid='$id'"); 
$heroid=mysql_fetch_row($result); 
$result2 = mysql_query("SELECT name FROM hero WHERE ID = 'heroid[0]'"); 

$heroname = mysql_fetch_row($result2); 
echo "User $id has a character named $heroname[0]"; 
$heroname = mysql_fetch_row($result2); 
echo "User $id has a character named $heroname[0]"; 
.. 

這可以通過單個查詢來完成嗎？

Answer 1

是的。你可以這樣做：

SELECT h.name 
FROM hero h 
INNER JOIN owner o ON o.heroid = h.id 
WHERE o.userid = $id