mysql - Mysql COUNT 订阅者为每个路由 id

Question

我有一个 MYSQL 查询问题，我需要一些帮助。我有 2 张桌子。

subscriber: id, campaign_id

route: id, service_code, shortcode

假设：campaign_id = 简码。

我想执行一个查询，该查询获取所有路由并计算每个路由的订阅者。

我希望输出如下：

Route | COUNT

44123 | 12

44566 | 48

44213 | 2

etc

你能帮我吗？

Answer 1

JOIN这两个表，然后使用COUNTand GROUP BY。就像是：

SELECT
  service_code, COUNT(COALESCE(s.id, 0)) AS `Count`
FROM route AS r 
LEFT JOIN Subscriber AS s ON r.shortcode = s.compaign_id
GROUP BY service_code

Answer 2

用这个：

select r.service_code, count(*)
from route r join subscriber s on s.campaign_id = r.shortcode
group by r.service_code;