如何在SQL中返回一个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多少次的计数。 有什么建议吗？

我尝试包括

COUNT(GROUP_CONCAT(subscription_plan_id))

但这不起作用。

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

所需的输出：

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

Answer 1

只需将count()放入select ：

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;

Answer 2

添加count和Group by subscription_plan_id

SELECT GROUP_CONCAT（subscription_plan_id），COUNT（subscription_plan_id）作为NumSubs来自在“ 2014-01-01”和“ 2014-01-31”之间创建的订阅中的NumSubs subscription_plan_id GROUP BY拥有COUNT（subscription_plan_id）> 1;