按外键和日期分组数据，按日期汇总

Posted 2023-02-16

【中文标题】按外键和日期分组数据，按日期汇总

【英文标题】：Group data by foreign key and date with total by date

【发布时间】：2021-03-09 07:15:45

【问题描述】：

我需要帮助来选择按组织和日期进行的每日付款和分组。 按日期分组，然后是付款总数和每天的付款总额 表格如下，

organizations 
-----------------------------
|    id       |    name     |
+-------------+-------------+
|    1        |    org_1    |
+-------------+-------------+
|    2        |    org_2    |
+-------------+-------------+
|    3        |    org_2    |
-----------------------------

payments
------------------------------------------------------------
|   id      |  org_id    |    amount   |    date_created   |
+-----------+------------+-------------+-------------------+
|    1      |    2       |    20       |   2020-11-06      |
+-----------+------------+-------------+-------------------+
|    2      |    2       |    10       |   2020-11-06      |
+-----------+------------+-------------+-------------------+
|    3      |    1       |    50       |   2020-11-05      |
+-----------+------------+-------------+-------------------+
|    4      |    2       |    10       |   2020-11-05      |
------------------------------------------------------------

预期结果

----------------------------------------------------------------------------------------------
| date_created   |   total_amount |   num_payments    |  org_1    |    org_2    |    org_3   |
+----------------+----------------+-------------------+-----------+-------------+------------+
|   2020-11-06   |     30.00      |      2            |    0      |     2       |    0       |
+----------------+----------------+-------------------+-----------+-------------+------------+
|   2020-11-05   |     60.00      |      2            |    1      |     1       |    0       |
+----------------+----------------+-------------------+-----------+-------------+------------+

【参考方案1】：

使用条件聚合：

select p.date_created,
    sum(p.amount) as total_amount,
    count(*) as num_payments,
    sum(case when o.name = 'org_1' then p.amount else 0 end) as org_1,
    sum(case when o.name = 'org_2' then p.amount else 0 end) as org_2,
    sum(case when o.name = 'org_3' then p.amount else 0 end) as org_3
from payments p
inner join organizations o on o.id = p.org_id
group by p.date_created

【讨论】：

谢谢，但您的查询将组织的数量限制为只有这 3 个如果添加新组织会发生什么情况

@Wells：那么您需要在select 子句中添加更多条件表达式。否则，您需要动态 SQL，这要复杂得多。