如何在MySQL中计算结果中的结果？

我有一张从几家不同的在线商店（如Ebay/Amazon等）购买的商品表。在今天之前，我只想根据每件商品的制造年份和制造商对其进行分组

所以，结果会是这样的

total  year  manufacturer
100    1999  man_a
32     2002  man_b

现在，我想通过每件商品来自哪个商店来缩小我的数量。总之，我想知道某一年有多少物品是由某一制造商生产的，还有多少是在易趣、亚马逊等网站上找到的。结果应该与此类似（至少提供相同的数据）

我可以这样做吗？如果可以，怎么做

这是我用来分组年份和制造商的查询，如果需要的话

SELECT `year`, `manufacturer`, COUNT(id) AS `total` FROM `items` GROUP BY `manufacturer`, `year` ORDER BY `total` DESC LIMIT 10;

谢谢

使用：

  SELECT `year`, 
         `manufacturer`, 
         COUNT(id) AS `total`,
         SUM(CASE WHEN store = 'ebay' THEN 1 ELSE 0 END) AS ebay_count,
         SUM(CASE WHEN store = 'amazon' THEN 1 ELSE 0 END) AS amazon_count
    FROM `items` 
GROUP BY `manufacturer`, `year` 
ORDER BY `total` DESC 
   LIMIT 10;

  SELECT `year`, 
         `manufacturer`, 
         COUNT(id) AS `total`,
         SUM(CASE WHEN store = 'ebay' THEN 1 ELSE 0 END) AS ebay_count,
         SUM(CASE WHEN store = 'amazon' THEN 1 ELSE 0 END) AS amazon_count
    FROM `items` 
GROUP BY `manufacturer`, `year` 
ORDER BY `total` DESC 
   LIMIT 10;