Question

我在确定如何对不同行进行求和时遇到麻烦，但是将每个分组的第一行用作起点。

我有一个看起来像这样的表：

+------+------+----------+---------------+----------+-------+
| Dim1 | Dim2 |   Date   | beg_Inventory | purchase | sales |
+------+------+----------+---------------+----------+-------+
| x    | y    | 1/1/2019 |           100 |       50 |    20 |
| x    | y    | 1/2/2019 |               |       70 |    80 |
| x    | y    | 1/3/2019 |               |       40 |    60 |
| x    | y    | 1/4/2019 |               |       30 |    50 |
| x    | y    | 1/5/2019 |               |      100 |    10 |
| x    | z    | 1/1/2019 |            65 |       10 |    50 |
| x    | z    | 1/2/2019 |               |       20 |     5 |
| x    | z    | 1/3/2019 |               |       40 |     5 |
+------+------+----------+---------------+----------+-------+

我想要一个看起来像这样的结果

+------+------+----------+---------------+----------+-------+------------+
| Dim1 | Dim2 |   Date   | beg_Inventory | purchase | sales | ending_inv |
+------+------+----------+---------------+----------+-------+------------+
| x    | y    | 1/1/2019 |           100 |       50 |    20 |        130 |
| x    | y    | 1/2/2019 |               |       70 |    80 |        120 |
| x    | y    | 1/3/2019 |               |       40 |    60 |        100 |
| x    | y    | 1/4/2019 |               |       30 |    50 |         80 |
| x    | y    | 1/5/2019 |               |      100 |    10 |        170 |
| x    | z    | 1/1/2019 |            65 |       10 |    50 |         25 |
| x    | z    | 1/2/2019 |               |       20 |     5 |         40 |
| x    | z    | 1/3/2019 |               |       40 |     5 |         75 |
+------+------+----------+---------------+----------+-------+------------+

期末库存为beg_inventory +购买-销售，每个dim1和dim2分组的第一行，即第一行为100 + 50-20 = 130 但是，在第二行中，它必须使用我们计算出的130，并在下一行中使用购买和销售来获得130 + 70-80 = 120，依此类推，按dim1和dim2分组并按日期排序。

谢谢。

Answer 1

尝试并使用first_value()在窗口中获取beg_inventory的第一个值，然后向其添加窗口化的sum()的购买和销售。

SELECT dim1,
       dim2,
       date,
       beg_inventory,
       purchase,
       sales,
       first_value(beg_inventory) OVER (PARTITION BY dim1,
                                                     dim2
                                        ORDER BY date)
       +
       sum(purchase - sales) OVER (PARTITION BY dim1,
                                                dim2
                                   ORDER BY date) ending_inv
       FROM elbat
       ORDER BY dim1,
                dim2,
                date;

Answer 2

所有行的公式对我来说都是相同的

SELECT t.*,
       SUM(COALESCE(beg_Inventory, 0) + purchase - sales) OVER (PARTITION BY dim1, dim2 ORDER BY date) as ending_inv
FROM t
ORDER BY dim1, dim2, date;

SQL-如何在不同的行上求和，而第一行的方程式不同

2 个答案: