如何從加入 SQL 中的表中按日期對 Id 進行匯總和計數

Question

我需要幫助，我有 2 個表station_levy和market_levy我正在嘗試對兩個表中完成的所有交易進行分組，查找總數並計算按日期分組的交易數量。

表格如下

station_levy

| station_levy_id | amount_tendered | transaction_datetime |
| --------------- | --------------- | -------------------- |
|        1        |       10        |       2021-02-01     |
|        2        |        5        |       2021-02-01     |
|        3        |       10        |       2021-02-03     |
|        4        |       10        |       2021-02-04     |

market_levy

| market_levy_id  | amount_tendered | transaction_datetime |
| --------------- | --------------- | -------------------- |
|        1        |        2        |       2021-02-01     |
|        2        |        3        |       2021-02-02     |
|        3        |        2        |       2021-02-03     |
|        4        |        2        |       2021-02-04     |

我試過了，但它沒有按日期分組

SELECT transaction_datetime, amount_tendered
FROM market_levy

UNION ALL

SELECT transaction_datetime, amount_tendered
FROM station_levy 
GROUP BY DATE(transaction_datetime)

ORDER BY DATE(transaction_datetime)

預期結果

| trans_count     | total_tendered  | transaction_datetime |
| --------------- | --------------- | -------------------- |
|        3        |       17        |       2021-02-01     |
|        1        |        3        |       2021-02-02     |
|        2        |       12        |       2021-02-03     |
|        2        |       12        |       2021-02-04     |

Answer 1

在子查詢中UNION您的表，並在此基礎上進行聚合和分組：

select count(1) as trans_count
       ,sum(amount_tendered) as amount_tendered
       ,DATE(transaction_datetime) as transaction_datetime
from
  (select station_levy_id as trans, amount_tendered, transaction_datetime
  from station_levy
  union all
  select market_levy_id as trans, amount_tendered, transaction_datetime
  from market_levy) temp
group by DATE(transaction_datetime)

請參閱SQL 小提琴中的結果