上面的查询将根据所有者对其进行分组，并根据服务出现的次数对其进行排序（降序），从而为您提供服务的小狗最多的所有者。

SELECT Top 1 o.Owner_Name  --Owner with most servicing
FROM Owner o
JOIN Puppys p ON o.Owner_ID = p.Owner_ID
JOIN Service_Done c ON c.Puppy_ID = p.Puppy_ID
GROUP BY o.Owner_ID  --grouping based on owner
ORDER BY count(*) DESC --order in descending order on the count of occurences

以下将返回前5名的主人谁的宠物服务最多。

SELECT 
    a.`Owner_ID`,
    a.`Owner_Name`,
    COUNT(*) as `Times_Serviced`
FROM `Owner` a
JOIN `Puppys` b
ON a.`Owner_ID` = b.`Owner_ID`
JOIN `Service_Done` c
ON c.`Puppy_ID` = b.`Puppy_ID`
GROUP BY a.`Owner_ID`
ORDER BY count(*) DESC
LIMIT 5;

通过改变分组方式，您还可以退回服务最多的宠物。您还可以按年份（或其他时间段）对结果进行分组。