Mysql SQL查询应该聚合每行数据，而不是多行数据

我希望列出每行调查的总视图：

CREATE TABLE IF NOT EXISTS `survey` (
      `id` int(6) unsigned NOT NULL,
      `title` varchar(200) NOT NULL,
      `url` varchar(200) NOT NULL,
      PRIMARY KEY (`id`)
    ) DEFAULT CHARSET=utf8;
    INSERT INTO `survey` (`id`, `title`, `url`) VALUES
      ('1', 'ants on the hill', 'https://mypoll.io/xyz'),
      ('2', 'crocs in the swamp', 'https://mypoll.io/xyz'),
      ('3', 'baboon on the loose', 'https://mypoll.io/another-term.');


      CREATE TABLE IF NOT EXISTS `views` (
      `id` int(6) unsigned NOT NULL,
      `poll_id` int(6) unsigned NOT NULL,
      `count` int(6) NOT NULL,
       PRIMARY KEY (`id`),
       FOREIGN KEY (poll_id) REFERENCES survey(id)
    ) DEFAULT CHARSET=utf8;
    INSERT INTO `views` (`id`, `poll_id`, `count`) VALUES
      ('1', 1, 1),
      ('2', 2, 1),
      ('3', 2, 1),
       ('4', 3, 1);

我目前拥有的：

SELECT s.*, COALESCE(v.totalViews, 0) as totalViews 
          FROM survey s
          LEFT JOIN (SELECT id, poll_id, count(id) AS totalViews
          FROM views GROUP BY id) as v on v.poll_id = s.id

我希望最终的结果是这样的

id  title               url                     totalViews
1   ants on the hill    https://mypoll.io/xyz   1
2   crocs in the swamp  https://mypoll.io/xyz   2
3   baboon on the loose https://mypoll.io/another-term. 1

---

示例Fiddle:

您需要对子查询做一个小的调整，从SELECT中删除

id

列，因为它不是必需的，而是在

poll\u id

上进行分组

SELECT poll_id, count(id) AS totalViews
      FROM views GROUP BY poll_id

---

您在错误的列上加入和聚合。您只需要

poll\u id

：

SELECT s.*, COALESCE(v.totalViews, 0) as totalViews 
FROM survey s LEFT JOIN
     (SELECT poll_id, count(id) AS totalViews
      FROM views 
      GROUP BY poll_id
     ) v
     ON v.poll_id = s.id;

---

是一个SQL提琴。

您不应该在查询中使用

sum（count）

（而不是

count（id）

）吗

SELECT poll_id,title,url, sum(`count`) totalViews FROM survey s
LEFT JOIN views v ON v.poll_id= s.id
GROUP BY poll_id

否则，

视图

中的实际

计数将不会考虑在结果中

看