mysql - 如何在 sql 中返回 group_concat 的计数？

Question

下面的查询返回用户拥有的所有不同订阅。在另一列中，我想返回给定订阅发生的次数。关于如何做到这一点有什么建议吗？

我试过包括

COUNT(GROUP_CONCAT(subscription_plan_id))

但它不起作用。

SELECT GROUP_CONCAT(subscription_plan_id)
FROM
  subscriptions
WHERE 
  created_at BETWEEN '2014-01-01' AND '2014-01-31'
GROUP BY
  user_id
HAVING
  COUNT(subscription_plan_id) > 1

期望的输出:

group_concat...count
1,2,3...2
2,3...5

Answer 1

只需将 count() 放在 select 中:

SELECT GROUP_CONCAT(subscription_plan_id), COUNT(subscription_plan_id) as NumSubs
FROM subscriptions
WHERE created_at BETWEEN '2014-01-01' AND '2014-01-31'
GROUP BY user_id
HAVING COUNT(subscription_plan_id) > 1;