mysql group_concat里面有一个计数? [英] mysql group_concat with a count inside?

问题描述

我有2个表，用户和关注者.下表后面有一个名为状态的列.我想根据状态对每个用户进行分组的次数进行计数.

i have 2 tables, users and follows. table follows has a column named status. I would like to count how many follows each user has grouping by the status.

下面的查询返回每个用户的每种状态类型的记录.

The query below returns a record for each status type for each user.

SELECT users.name as user_name, f.status, count(f.id) 
FROM users
JOIN application_follows f ON f.user_id = users.id
GROUP BY users.id, f.status
ORDER BY users.id

返回类似:

user_name     status     count

mike          new         10
mike          old         5
tom           new         8
tom           old         9

但是我想要更友好的东西:

but i would like something more friendly like:

user_name     status_count

mike          new,10|old,5
tom           new,8|old,9

使用group_concat进行了尝试并计数，但没有成功.有任何线索吗?

tried using group_concat and count but didnt work. Any clues?

推荐答案

您需要使用GROUP BY两次，首先从下面的(user_id，status)开始获取计数，然后在user_id上从连接表到concat:

You need to use GROUP BY twice, first on (user_id, status) from follows to get counts then on user_id from joined table to concat:

SELECT users.name, GROUP_CONCAT( CONCAT(f.status, ',', f.cnt) SEPARATOR '|' )
FROM users 
JOIN
( SELECT user_id, status, count(id) AS cnt
  FROM application_follows
  GROUP BY user_id, status ) f
ON f.user_id = users.id
GROUP BY users.id

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