将单行数据插入多行table

Question

概要：如何编写 SQL 代码以将平面文件中的一条记录插入要插入 SQL 服务器 table 的单独记录中 table。

细节：我有一个 table 来记录租赁付款。对于每份租赁协议，到期日始终是每月的第一天。 table 中每个月在租约期间都有一个条目。为简单起见，假设有一份从 2019 年 9 月 1 日到 2020 年 8 月 31 日的租赁合同。table 看起来像这样：

+------------------------------------------------------+
| CONTRACT_ID | DUE_DATE_DT | INVOICE_ID | RENTAL_AMT  |
+-------------+-------------+------------+-------------+
| 12345       |    9/1/2019 |            |             |
+-------------+-------------+------------+-------------+
| 12345       |   10/1/2019 |            |             |
+-------------+-------------+------------+-------------+
...
+-------------+-------------+------------+-------------+
| 12345       |    8/1/2020 |            |             |
+-------------+-------------+------------+-------------+

发票通常为一个日历月，但有时可能有两三个月，因为供应商正在追赶。数据以平面文件形式接收，样本如下所示：

Contract  Rental Period From Date  Rental Period To Date  Invoice Number   Amount
31125      9/1/2019                  9/30/2019             6378            400.00  (standard scenario)
12345      9/1/2019                 11/30/2019             789             150.00  (multi-month scenario)

平面文件中的数据需要存储在 table 中的三个单独的记录中：

+------------------------------------------------------+
| CONTRACT_ID | DUE_DATE_DT | INVOICE_ID | RENTAL_AMT  |
+-------------+-------------+------------+-------------+
| 12345       |    9/1/2019 |   789      |   50.00     |
+-------------+-------------+------------+-------------+
| 12345       |   10/1/2019 |   789      |   50.00     |
+-------------+-------------+------------+-------------+
| 12345       |   11/1/2019 |   789      |   50.00     |
+-------------+-------------+------------+-------------+

提前致谢。

Answer 1

您可以尝试使用递归CTE。考虑一下：

CREATE TABLE #RawData(Contract int, Rental_Period_From Date, Rental_Period_To Date, Invoice_Number int, Amount Decimal(10,2))
INSERT INTO #RawData VALUES(31225, '9/1/2019','9/30/2019', 6378,400.00)
INSERT INTO #RawData VALUES(12345, '9/1/2019','11/30/2019', 789,150.00)


;WITH CTE
AS
(
select Contract,Rental_Period_From DueDate,Invoice_Number,Amount, 0 MonthCounter, Rental_Period_To from #RawData
UNION ALL
SELECT Contract, DATEADD(month,MonthCounter+1,DueDate),Invoice_Number,Amount, MonthCounter,Rental_Period_To   from CTE
WHERE DATEADD(month,MonthCounter+1,DueDate) <= Rental_Period_To

)
SELECT CONTRACT, DueDate,Invoice_Number, CAST(Amount / (SELECT COUNT(*) 
                FROM CTE t1 WHERE t1.Contract = t2.Contract ) as decimal(10,2)) Amount 
FROM CTE t2

将单行数据插入多行table

Insert a single line of data into multiple rows of table

sql-server

etl

database-programming