我有一个有效的sql搜索查询，但它只有在投票表中存在投票时才有效。
mysql_query("SELECT m.Title, r.Subject, SUM(v.IsGood) AS Good, SUM(v.IsBad) AS Bad
FROM Movies m
JOIN Reviews r
ON m.ID=r.MovieID
JOIN Votes v
ON r.ID=v.ReviewID
WHERE (m.Title LIKE '%" . $search . "%' OR r.Subject LIKE '%" . $search . "%')
GROUP BY m.Title, r.Subject
ORDER BY SUM(v.IsGood) DESC, SUM(v.IsBad) ASC LIMIT 10")
所以我在下面把它改成了这个，这样无论是否有0票，它都应该显示出来。但它没有得出任何结果，有人能告诉我我做错了什么吗？
mysql_query("SELECT m.Title, r.Subject, COUNT(v.ReviewID) AS Rvotes, SUM(v.IsGood) AS Good, SUM(v.IsBad) AS Bad
FROM Movies m
JOIN Reviews r
ON m.ID=r.MovieID
JOIN Votes v
ON r.ID=v.ReviewID
WHERE (m.Title LIKE '%" . $search . "%' OR r.Subject LIKE '%" . $search . "%')
GROUP BY m.Title, r.Subject, v.ReviewID
HAVING Rvotes >= 0
ORDER BY SUM(v.IsGood) DESC, SUM(v.IsBad) ASC LIMIT 10")
假设您想要结果，即使投票表中不存在投票，LEFT JOIN选票表格。
mysql_query("SELECT m.Title, r.Subject, SUM(v.IsGood) AS Good, SUM(v.IsBad) AS Bad
FROM Movies m
JOIN Reviews r
ON m.ID=r.MovieID
LEFT JOIN Votes v
ON r.ID=v.ReviewID
WHERE (m.Title LIKE '%" . $search . "%' OR r.Subject LIKE '%" . $search . "%')
GROUP BY m.Title, r.Subject
ORDER BY SUM(v.IsGood) DESC, SUM(v.IsBad) ASC LIMIT 10")
注意：我修改了您的初始查询（而不是第二个），因为您说它仍然没有提供您想要的内容。