小编Jan*_*ani的帖子

如何使用 Sum 和 Count 函数连接多个表进行聚合？

我正在尝试的查询如下：

Select
  campaigns.id,
  campaigns.name,
  Count(landers.campaign_id) As landers_count,
  Sum(conversions.revenue) As total_revenue
From
  campaigns Left Join
  conversions
    On campaigns.id = conversions.campaign_id Left Join
  landers
    On campaigns.id = landers.campaign_id
Group By
  campaigns.id

我什至尝试过外部连接，但没有运气，而且我得到的结果不准确。

我的示例表如下：

活动表：

| id | name           |
+----+----------------+
| 1  | Facebook Ads   |
| 2  | Bing Ads       |
| 3  | Direct Mailing |
| 4  | Solo Ads       |

兰德斯表：

| id | name        | campaign_id |
+----+-------------+-------------+
| 1  | Lander …