MySQL 联合计数

Question

首先让我展示我的表格数据，然后我将解释我的问题。

MySQL 表结构

CREATE TABLE more_tags (
tag_id INT UNSIGNED NOT NULL AUTO_INCREMENT,
more_id INT UNSIGNED NOT NULL,
user_id INT UNSIGNED NOT NULL,
tag_name VARCHAR(255) NOT NULL,
PRIMARY KEY (tag_id),
UNIQUE KEY (more_id, user_id, tag_name)
);

CREATE TABLE tags(
tag_id INT UNSIGNED NOT NULL AUTO_INCREMENT,
another_id INT UNSIGNED NOT NULL,
user_id INT UNSIGNED NOT NULL,
tag_name VARCHAR(255) NOT NULL,
PRIMARY KEY (tag_id),
UNIQUE KEY (another_id, user_id, tag_name)
);

more_tads表数据

tag_id  tag_name
10      apple 
192     apple 
197     apple 
203     apple 
207     apple 
217     news 
190     bff
196     cape

标记表格数据

tag_id  tag_name
1       apple 
2       time 
3       bff

好的，我之前问过一些类似的问题。但现在由于某种原因，我无法获得查询来计算两个表中的标签，它只计算一个表中的标签，如下例所示

当前输出

tag_id  tag_name    num
1       apple       5
2       bff         1
3       cape        1
4       time        1

但我想对所有相似的标签进行分组，并计算它们在表格中的出现次数，如下例所示

期望的输出

tag_id  tag_name    num
1       apple       6
2       bff         2
3       cape        1
4       time        1

当前 MySQL 查询

SELECT *
FROM(SELECT `more_tags`.`tag_id`, `more_tags`.`tag_name`, COUNT(`more_tags`.`tag_name`) as 'num' 
FROM `more_tags` 
INNER JOIN `users` ON `more_tags`.`user_id` = `users`.`user_id` 
WHERE `users`.`active` IS NULL 
AND `users`.`deletion` = '0' 
GROUP BY `more_tags`.`tag_name`
UNION(
SELECT `tags`.`tag_id`, `tags`.`tag_name`, COUNT(`tags`.`tag_name`) as 'num' 
FROM `tags` 
INNER JOIN `users` ON `tags`.`user_id` = `users`.`user_id` 
WHERE `users`.`active` IS NULL 
AND `users`.`deletion` = '0' 
GROUP BY `tags`.`tag_name`))
AS table_1 
GROUP BY `tag_name`  
ORDER BY `tag_name` ASC

Answer 1

这将输出你想要的结果。只需在子查询中添加用户加入即可。

SELECT a.tag_id, a.tag_name, SUM(a.num)
FROM (
     SELECT tag_id, tag_name, SUM(1) as num  FROM tags
        GROUP BY tag_name
     UNION
     SELECT tag_id, tag_name, SUM(1) as num  FROM more_tags
        GROUP BY tag_name
      ) a
GROUP BY a.tag_name