mysql - 在 MySQL 中进行计数

Question

我有以下两个表 -- userprofile 和 videoinfo。 videoInfo 有一个 FK 到 userprofile。

CREATE TABLE `userprofile_userprofile` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `full_name` varchar(100) NOT NULL,
   ...
 )

CREATE TABLE `userprofile_videoinfo` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(256) NOT NULL,
  `uploaded_by_id` int(11) NOT NULL,
  ...
  KEY `userprofile_videoinfo_e43a31e7` (`uploaded_by_id`),
  CONSTRAINT `uploaded_by_id_refs_id_492ba9396be0968c` FOREIGN KEY (`uploaded_by_id`) REFERENCES `userprofile_userprofile` (`id`)
)

我将使用什么 SQL 语句来显示每个用户配置文件拥有的视频数并按 COUNT 排序？

Answer 1

SELECT u.id as userId, count(v.uploaded_by_id) as videosCount
FROM userprofile_userprofile u
    LEFT OUTER JOIN userprofile_videoinfo v
        ON v.uploaded_by_id = u.id
GROUP BY u.id
ORDER BY count(v.uploaded_by_id) DESC